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\title{TEI EDW26\\An introduction to the Text Encoding Initiative}
\author{Lou Burnard}
\date{6 Aug 1991}
\date{Rev. May 1992}
\begin{document} \maketitle
\begin{abstract}This paper\footnote{First published in Greenstein, D.I., ed,
\smartitalic{Modelling Historical Data} (G\"{o}ttingen, Max-Planck-Inst.
f\"{u}r Geschichte, 1991).} outlines the origins and goals of the Text
Encoding Initiative, an international research project which aims
to provide guidelines for the standardisation of electronic texts
in research.  It begins with a re-statement of the
goals of the project, placed in the current research context, and
then gives a brief description of its nature and scope,
with attention to its potential for the handling of the full
diversity of textual materials likely to be of interest to social
historians.\end{abstract}
\section{What is the Text Encoding Initiative?}
\par
The Text Encoding Initiative is an international research
project, the aim of which is to develop and to disseminate
guidelines for the encoding and interchange of machine-readable
texts. It is sponsored by the Association for Computers and the
Humanities (ACH), the Association for Computational Linguistics (ACL),
and the Association for Literary and Linguistic Computing (ALLC).  The
project is funded by the U.S. National Endowment for the
Humanities, DG XIII of the Commission of the European
Communities, the Canadian Social Science and Humanities Research Council
and the Andrew W. Mellon Foundation.  Equally
important has been the donation of time and expertise by the many
members of the international research community who have served
on the TEI's various
Working Committees and Working Groups.
\par
The project originated in a conference held at Vassar College in
the winter of 1987\footnote{See `Report of Workshop on
Encoding Principles' \smartitalic{Literary and Linguistic Computing} 3.2
(1988).}. The conference was organised by the ACH with
funding from NEH. Thirty-one invited scholars, representatives of
scholarly organizations and archive directors from North America,
Europe and the Middle East participated in two days of intense
discussion from which emerged a consensus, expressed in the
``Poughkeepsie Principles'' discussed below. The success of
this conference resulted in the establishment of the Text
Encoding Initiative as a co-operative venture sponsored jointly
by the ACH, the ACL and the ALLC and directed by a steering
committee comprising two representatives from each of these
associations.
\par  The TEI Steering Committee formulated a work plan  to achieve
the goals proposed at the Vassar Conference, and then approached
fifteen leading scholarly organizations in North America and
Europe to nominate representatives to an Advisory Board. This
Board met for the first time in Chicago in February 1989,
approved the work plan  with some modifications and nominated
some members to the four working committees of the TEI. It will
meet again in 1992 to review the final product of the TEI.
\par  During the first funding cycle of the TEI (June 1988-June
1990), work was carried out in four large working committees,
with membership drawn from Europe and North America, and from a
wide range of disciplines. The members of the largest committee,
for example, had backgrounds in computer science, textual
editing, theology, software development, linguistics, philosophy
and history and  were from Norway, Belgium, Germany, Spain and
the UK as well as the USA. Each of the four committees proposed a
variety of recommendations in distinct areas of text encoding
practices. These found expression in the first draft of the TEI
Guidelines, a large (300 page) report which was widely
distributed in Europe, North America and elsewhere in November
1990. As noted above, however, the present article will not
attempt to summarise these Recommendations\footnote
{ACH-ACL-ALLC \smartitalic{Guidelines for the encoding and interchange of
machine-readable texts} edited by Lou Burnard and
C.M. Sperberg-McQueen (Chicago and Oxford, Text Encoding Initiative,
October, 1990), hereafter ``Guidelines'' or ``P1''.} themselves,
as a number of summary  articles have already appeared\footnote
{Examples include \smartitalic{Humanistiske Data} 3-90; \smartitalic
{ACH Newsletter} 12 (3- 4); \smartitalic{EPSIG News} 3(3); \smartitalic
{SGML Users Group Newsletter} 18; \smartitalic{ACLS Newsletter}2/4 and
elsewhere.  A fuller summary is to appear as Burnard `The TEI:
a progress report' in \smartitalic{Proceedings of the 11th ICAME
Conference, Berlin, 1990}, ed G.Leitner. Encoding
principles of the TEI are discussed in Sperberg-McQueen, `Texts in the
electronic age: textual study and text encoding, \linebreak with
examples from medieval texts', in \smartitalic{Literary and Linguistic
Computing} (6.1,~1991).}.
\par
During the second TEI funding cycle (June 1990-June 1992) the
initial recommendations are being reviewed and extended by about
a dozen different specialist working groups. The membership of
these is, again, as broadly based as possible, while the topics
they are currently addressing include character sets; textual
criticism; hypermedia; mathematical formulae and tables; language
corpora and spoken texts; physical description of printed and
manuscript sources; formal characteristics of literary genres in
prose, drama and verse; general linguistics; electronic
dictionaries, lexica and terminology banks; and last, but by no
means least, historical sources. Each work group is charged with
the production of a set of recommendations for change to the
Guidelines and the testing of their provisions in the Group's
chosen field. These reports will form one of three sources of
input to the final revision of the current draft proposals, for
review during the coming winter.
\par
In the summer of 1991, a series of TEI Workshops was organised,
at Tempe, Oxford and Providence. These attracted a large number
of vociferous discussants, from a wide variety of backgrounds,
including professional software developers, librarians, computer
scientists as well as researchers and teachers from most of the
disciplines in the humanities. The emphasis here was on using the
Guidelines as they stood with currently available software and on
putting their proposals to the test of real data.
\par
Similarly pragmatic concerns underly the second source of
modifications to the current draft: the experiences of the
``affiliated projects''. Some fifteen major research projects,
on both sides of the Atlantic, have signed affiliation agreements
with the TEI which involve, amongst other things, the testing of
the Guidelines against realistically sized samples of the various
textual resources which each project is engaged in creating and a
detailed report on the problems encountered and solutions found.
These projects include major linguistic corpus building ventures
such as the British National Corpus and the ACL Data Collection
Initiative; projects engaged in the creation of large general
purpose historical or literary corpora such as the Brown
University Women Writers Project or Harvard University's Perseus
Project; as well as smaller individual projects aiming to produce
scholarly electronic editions of major authors such as Middleton,
Milton or Nietzsche.
\par
The final source of comment and revision is the public at large,
which has reacted with surprising and occasionally embarassing
enthusiasm to the original draft proposals. Over a hundred sets
of individual comments and criticisms, some quite detailed, have
already been received, and it is hoped that this public
discussion will continue during the remainder of the project's
lifetime. It has been often remarked that standards cannot be
enforced by fiat: they must be accepted voluntarily if they are
to achieve any permanent standing. To that end, the TEI has
always been anxious to stimulate informed discussion of its
proposals in as many and as diverse forums as there are listeners
willing to hear.
\par
The task of co-ordinating the working groups and committees, and
of combining their drafts for publication is carried out by two
editors, one European and one American, while the project as a
whole is managed by the steering committee. The final
deliverables of the project, which will include a substantial
reference manual and a number of tutorial guides, will be
presented to the Advisory Board in the spring of 1992, in time
for final publication at the end of the second funding cycle in
June of that year.
\section{TEI Design Goals}
\par  As mentioned above, the basic design goals of the TEI
Guidelines were  determined by the results of a planning
conference held at Vassar College in Poughkeepsie, New York, at
the outset of the project.  That planning conference agreed on
the following statement of principles:
\begin{itemize}
\item The guidelines are intended to provide a standard format for
   data interchange in humanities research.
\item The guidelines are also intended to suggest principles for
 the encoding of texts in the same format.
\item The guidelines should
\begin{itemize}
\item define a recommended syntax for the format,
\item define a metalanguage for the description of text-encoding
     schemes,
\item describe the new format and representative existing schemes
      both in that metalanguage and in prose. \end{itemize}
\item The guidelines should propose sets of coding conventions
suited for various applications.
\item The guidelines should include a minimal set of conventions
 for encoding new texts in the format.
\item The guidelines are to be drafted by committees on text
documentation; text representation; text interpretation and
analysis; metalanguage definition and description of existing and
proposed schemes. These committees will be
coordinated by a steering committee of representatives of the
principal sponsoring organizations.
\item Compatibility with existing standards will be maintained as
  far as possible.
\item A number of large text archives have agreed in principle to
  support the guidelines in their function as an interchange
format.  We encourage funding agencies to support development of
   tools to facilitate this interchange.
\item Conversion of existing machine-readable texts to the new
format involves the translation of their conventions into the
syntax of the new format.  No requirements will be made for the
  addition of information not already coded in the texts.
\end{itemize}
\par  The mandate of creating a common interchange format requires
the specification of a specific markup syntax as well as the
definition of a large predefined tag set and the provision of
mechanisms for extending the markup scheme.  The mandate to
provide guidance for new text encodings (``suggest principles
for text encoding'') requires that recommendations be made as
to what textual features should be recorded in various
situations.  The TEI Guidelines were thus, from the start,
concerned both with {\sc how} encoding should be preserved
for interchange purposes and {\sc what} should in fact be
encoded, a point to which I return below.
\par
As well as attempting to balance the membership of the original
committees geographically and by discipline, an attempt was made
to focus the work of each committee on areas where substantial
agreement existed among the different parties, rather than to
revive or rehearse well recognised disagreements.  The guiding
principle was to facilitate consensus rather than controversy.
Inevitably, this approach runs the risk of pleasing no-one, by
being void of substantial content, or refusing to take a stand on
any issue. In practice however, the reception of the Guidelines
shows that these dangers were safely avoided. Moreover, despite
the diversity of backgrounds of those involved, a pleasing
discovery was the number of fundamentally identical encoding
problems to be found in apparently different types of material.
The task of encoding (for example) the different strata of a
manuscript tradition poses formally identical problems with those
of encoding in parallel multiple linguistic analyses of a  given
sentence. The task of representing hypertextual links in a
document is strikingly similar to that of representing literary
allusions or cross references. The problem of preserving the
physical appearance of a text together with multiple
interpretations derived from it is common to almost every text-based
discipline.
\section{The need for interchange}
\par  The goal of the TEI is to develop and disseminate a set of
Guidelines for the interchange of machine-readable texts among
researchers, so as to allow easier and more efficient sharing of
resources for textual computing and natural language processing.
It needs to be stressed at the outset that the phrase ``machine-readable
texts'' is to be understood in the widest possible
sense. What, for example, do historians do with texts which is
fundamentally different from what linguists or social science
researchers or literary analysts do? In each case, the same
problems arise: an existing source must be represented
accurately, a set of interpretations about its component parts
must be specified, and some processing carried out. Sometimes the
processing will focus more on representation than on analysis (as
in the production of a new edition); at other times, the focus
will be on a particular kind of analysis (as in the extraction of
statistical data or the construction of a database). However, as
I and others have argued elsewhere,\footnote{`Primary to Secondary'
in Peter Denley and Deian Hopkins, eds. \smartitalic{History and
Computing} (Manchester: Manchester University Press, 1987).} a crucial
benefit of computer-aided research is the way in which it supports both
approaches. The creator of an appropriately marked-up electronic text can
have her cake and eat it too. Standardisation efforts which do not
address the issue of a neutral, processing-independent, view of
textual objects, but instead focus on standards in particular
application areas, thus fall somewhat short of realising the full
potential of electronic texts.
\par
Of course, in a world of unlimited resources, there would be no
particular need for interchange standards at all: each creator of
electronic texts could do so in glorious isolation. However, in
several areas of the research community, notably the expanding
field of natural language processing, a need for interchangeable
electronic resources is already widely recognised, on both
economic and methodological grounds. Economically, it is widely
accepted that the heavy cost of creating such resources as
language corpora and electronic lexica can only be justified if
the resources can be re-used by many projects.\footnote{A recent
EUROTRA-funded study (U. Heid, ``Eurotra-7: Feasibility and Project
Definition Study on the Reusability of Lexical and Terminological
Resources in Computerised Applications'', January, 1991) reported
on this and other aspects of `re-usability of lexical resources' in
considerable detail: its findings are equally relevant to
other disciplines.} Methodologically, the repeatability of
research results which forms an essential aspect of any empirical
research can best be guaranteed by the continued availability of
data sets for secondary analysis. Standardisation is easily
achieved where there is a broad consensus about the kinds of data
to be processed and the particular software packages to be used
(as has been, for example, the case for many years in social
science survey research). It is less simple where essentially
identical kinds of data resources (such as textual corpora)
contain matter of interest to distinct research communities
characterised by an immense variety of theoretical positions and
methods. Yet the same conceptual model of what texts actually are
should be applicable to all. This can only be achieved if
standardisation is expressed at a sufficiently general level to
allow for the widest variety of views.
\par  The TEI arose from a perceived need within one, comparatively
small, research community: that concerned with the encoding and
manipulation of purely textual data for purposes of descriptive
or corpus linguistics, stylistic analysis, textual editing and
other forms of what is broadly called `Literary and Linguistic
Computing' (LLC). There has recently been an interesting
convergence between the needs and abilities of that community
with those of the somewhat larger body of researchers concerned
with the computational analysis of natural language (NLP) whether
for natural language understanding, generation or translation
systems. Straddling the two communities are those concerned with
the creation of better, objectively derived, models of language
in use, whose methods have transformed current practices in
lexicography and language teaching. What links all of these
researchers is the need to process large amounts of textual data
in a wide variety of different styles. What the TEI offers them,
and others, is a model for the standardisation of textual data
resources for interchange.
\par
It is helpful, when considering standardisation of electronic
resources, to distinguish the objects of standardisation (the
`what') from the particular representation recommended for it
(the `how'). Like other standardisation efforts, the TEI
Guidelines include both  recommendations about which textual
features should be distinguished when encoding texts from scratch
if the resulting text is to be of maximal usefulness to the
research community, and recommendations of specific practices in
the encoding of new texts. The `how' chosen by the TEI is based
on the international standard Standard Generalized Markup Language
(SGML), an informal introduction to
which is provided elsewhere in this volume. The `what' is rather
more difficult to summarise in a short document of this nature,
but some general remarks and a few specific examples are provided
below. Distinguishing these two aspects of standardisation is
particularly important for electronic resources, because of the
ease with which their representations may be changed.
\par  What is sometimes forgotten is that ease of conversion is
crucially dependent on the prior existence of an agreed set of
distinctions. The TEI attempts to make such an agreed set of
distinctions, by proposing an abstract data model consisting of
those features for which a consensus can be reached as to their
importance in a wide range of automatic analyses. To identify
these features, particular software systems may use entirely
different representation schemata: different representations will
be appropriate for different hardware environments, for different
software packages, for archival storage and in particular for the
exchange of data across particular networks.
\section{Structure and interpretation: the TEI topoi} \label{what}
\par  I suggested above that the primary function of markup was to
make explicit an interpretation of a text. Any standardisation
effort such as the TEI must therefore at some time grasp the
nettle of deciding which interpretations are to be favoured over
others. To put it another way, the TEI must at least attempt to
address the question as to which aspects or features of a text
should be made explicit by its markup.
\par  For some scholars, this is a simple issue. There are some
features of a text which are ``obvious'' and ``objective''
-- examples usually include major structural subdivisions such as
chapters or verse lines or entries in a charter. There are others
which are equally obviously ``pure interpretation'' -- such as
whether or not a passage in a prose text belongs to some
stylistic category, or is in a foreign language, or is a personal
name. As this last list perhaps indicates, for the present writer
this is a far from clear cut distinction. In almost every kind of
material, and especially in the kinds of materials studied by
historians, there is a continuum of categorisations, from things
about which almost everyone will agree almost all of the time,
down to things which almost no-one will identify in the same way
ever.
\par  The TEI therefore adopts a liberal policy. It proposes for
consideration a set of categories which wide consultation has
demonstrated to be of use to a broad consensus of researchers. It
proposes ways in which instances of those categories may be
marked up (as discussed in the last section). Researchers in
agreement as to the use of the categories so defined can thus
interchange texts, or (if you wish) interpreted texts. They can
do so moreover in a format which allows the disentangling of the
interpretation from the text stream, or its enrichment in a
controlled way. No claim is made as to the feasibility or
desirability of making such interpretations in a given case --
all that the TEI can or does offer is a way of making explicit
what has been done.
\par  The remainder of this paper discusses some concrete instances
of the kinds of textual feature which typify the current TEI
proposals.
\subsection{The structure of a TEI text}
\subsubsection{The TEI header}
All TEI-conformant texts contain (a) a \smartitalic{TEI
header} and (b) the transcription of the text proper.  The
TEI header provides information analogous to that provided by the
title page of a printed text. It contains a description of the
machine- readable text, a description of the way it has been
encoded, and a revision history; these are delimited by the
\tag{$<$file.description$>$}, the
\tag{$<$encoding.declarations$>$}, and the
\tag{$<$revision.history$>$} tags, respectively.  The first of
these identifies the electronic text as an object in its own
right, independent of its source or sources (which must however
be documented within it). The second supplies details of the
particular encoding practices or variations which characterise
the text, for example any special codebooks or other values used
within the body of the text and descriptions of the referencing
scheme or editorial principles applied. The header is, perhaps
surprisingly, the {\sc only} part of a TEI text which is
mandatory.
\subsubsection{Marking Divisions within a Text}
\par  The TEI recommendations categorise document elements as
either \smartitalic{structural} or \smartitalic{floating}.
Structural elements are constrained as to where they may appear
in a document; for example a \tag{$<$head$>$} or heading may not
appear in the middle of a \tag{$<$list$>$}. Floating elements, as
the name suggests, are less constrained and may appear almost
anywhere in a text: examples include \tag{$<$note$>$} or
\tag{$<$date$>$}. Intermediate between the two categories are so-
called \smartitalic{crystals}: these are floating features the
contents of which have an inherent structure, for example
\tag{$<$list$>$} or \tag{$<$citn$>$} elements.
\subsubsection{Structural features}
\par
The current recommendations
define a general purpose hierarchic structure, which has been
found to be suitable for a very large (perhaps surprisingly
large) variety of textual sources. In this, a text is divided
into an  optional \tag{$<$front$>$}, a \tag{$<$body$>$} and an optional
\tag{$<$back$>$}. The body of a text may be a series of paragraphs
(marked with \tag{$<$p$>$} \ldots \tag{$<$/p$>$}), or it may be
divided into chapters, sections, subsections, etc.  In the latter
case, the \tag{$<$body$>$} is divided into a series of elements
known generically as \smartitalic{div}s.  The largest subdivision
of a given text is tagged \tag{$<$div1$>$}, the next smallest
\tag{$<$div2$>$} and so on. Written prose texts may also be further
subdivided into \tag{$<$p$>$}s (paragraphs).  For verse texts, metrical
lines are tagged with the \tag{$<$l$>$} tag.
\subsubsection{Floating features}
\par As mentioned above, the current Guidelines propose names and
definitions for a wide variety of floating features.  Examples
include \tag{$<$head$>$} for titles and captions (not properly
floating, since they are generally tied to a particular
structural element); \tag{$<$q$>$} for quoted matter and direct
speech; \tag{$<$list$>$} for lists and \tag{$<$item$>$} for the
items within them; \tag{$<$note$>$} for footnotes etc.;
\tag{$<$corr$>$} for editorial corrections of the original source
made by the encoder;  and, optionally, a variety of lexically
`awkward' items such as \tag{$<$abbr$>$}eviations,
\tag{$<$acronym$>$}s, \tag{$<$number$>$}s, \tag{$<$name$>$}s,
\tag{$<$date$>$}s, \tag{$<$citn$>$} for bibliographic or other
citations, \tag{$<$address$>$} for street addresses and
\tag{$<$foreign$>$} for non-English words or phrases.
\subsection{Reference scheme}
\par The advantage of using a single hierarchic scheme as outline
above, is that a referencing scheme based on it can be
automatically generated. For example, a given paragraph will acquire a
number indicating its sequence within the enclosing \tag{$<$div$>$},
itself identified by its number within any enclosing \tag{$<$div$>$}
above it, and ultimately within the enclosing \tag{$<$text$>$}.
For example, the
value ``T98.1.9/12'' might identify the 12th paragraph in chapter 9
of book 1 of the text with number T98.
\par  To complement this kind of internal referencing system, the
Guidelines provide two distinct methods of marking other
reference schemes, such as page and line numbers.  The hierarchy
of volume, page, and line can be neatly expressed with a
concurrent markup stream separate from the main markup hierarchy
(see P1 section 5.6); for data entry purposes, however, the
simpler scheme we describe here may be more convenient. After
data entry, this markup can be transformed mechanically into that
required for a concurrent markup hierarchy, if that is supported
by the software in use.
\par  Page breaks, column breaks, and line breaks may be marked
with empty \smartitalic{milestone} elements: that is, tags such as
\tag{$<$line.break$>$} or \tag{$<$page.break$>$} which mark a
single point in the text, not a span of text, and therefore have
no corresponding end-tags. Such tags may have an {\it n\/}
attribute to supply the number of the page, column, or line
beginning at the tag explicitly, or may give only the number of
the first if subsequent ones can be calculated automatically.
This mechanism also allows for  the pagination etc. of more than
one edition to be specified by using an {\it ed\/} attribute.
\subsection{Descriptive vs presentational markup}
\par A matter of considerable controversy (and associated
misunderstanding) has been the question of whether or not aspects
of a text directly related to its physical appearance can or
should be marked up. For some researchers, and in many
applications, typographic features such as lineation or font are
of little or no importance. For others, they are the very subject
of interest. Because SGML focuses attention on
{\sc describing} a text, rather than attempting to
simulate its appearance, the TEI recommendations have proposed
that where it is possible to identify a structural (or floating)
feature by its function, then that is what should be primarily
tagged. This does not however mean that they provide no support
for cases where the exact purpose of some distinctly-rendered
part of a text cannot be determined. It is recognised that in
many cases it may be neither desirable nor possible to interpret
changes of rendering in this way.
\par  A global attribute {\it rendition\/} may be specified for
every tag in the TEI scheme, the value of which is a user-
specified string descriptive of the way that the current element
is rendered in the source being transcribed.\footnote{This implies
of course that the markup describes a single source.} In
most cases, a change in rendering and a change of element
coincide: this mechanism therefore reduces the amount of tagging
from what would be required if a separate set of tags were used
for rendering. Further reduction in tagging is provided by the
fact that the default value for a {\it rendition\/} attribute is that of
the immediately surrounding element (if any).
\par  In cases where a renditional change is not associated with
any discernible element, a special tag \tag{$<$highlighted$>$} may
be used, the sole function of which is to carry the
{\it rendition\/} attribute.
\par  No recommendations about the form of value to be supplied for
{\it rendition\/} attributes have yet been made: these are the subject of
current work in two working groups. Similar considerations apply
to the use of quotation marks and quoted passages within a text.
\subsection{Scope and coverage of P1}
\par  As an example of the scope and range of facilities which SGML
can support, I close with a brief summary of the full contents of
the current draft and a more detailed description of a few of the
more specialised kinds of textual features for which tags are
already proposed in the draft Guidelines.
\par  It should be stressed that the first draft of the Guidelines,
despite its weighty appearance (nearly 300 pages of closely
printed A4), is very much a discussion paper and far from being
complete or definitive.  Some characteristics of the TEI approach
are however already discernible which are unlikely to change.
One is a focus on the encoding of the content of text, rather
than its appearance -- as discussed above, this is also a
characteristic of SGML.  Another is the rigorous application of
Occam's razor: the TEI approach to the immense variety of text
types in the real world is to attempt to define a comparatively
small number of features which all texts share, and to allow for
these to be used in combination with user-definable sets of more
specialised features.\footnote{This has been termed the ``pizza
model'', by contrast with either the ``table d'h\^{o}te''
or the ``\`{a} la carte'' models. A choice of a small
number of bases is offered, each of which may be combined with a
large number of toppings.}
\par  The current draft has eight main sections, which are briefly
summarized below.
\par  Chapter 1 outlines the purpose and scope of the TEI scheme.
As outlined above, its main goals are both to facilitate data
interchange and to provide guidance for those creating new texts.
The desiderata of simplicity, clarity, formal rigour, sufficient
power for research purposes, conformance to international
standards, and independence of software, hardware or application
alike are stressed.
\par  Chapter 2 provides a gentle introduction to the basic
concepts of SGML and  also contains some more technical
information about the ways in which the TEI scheme uses the
standard.
\par  Chapter 3 addresses the problems of character encoding and
translation in a world dominated by the rival claims of ASCII and
EBCDIC.  If the goal is to provide machine-independent support
for all writing systems of all languages, these problems are far
from trivial.  The specific recommendations made are that only a
subset of the ISO-646 character set (sometimes known as ASCII)
can currently be relied on for data interchange, and that this
should be extended either by using the entity reference mechanism
provided by SGML or by using transliteration schemes.  It
proposes a powerful but economical way of documenting such
transliteration schemes by a formal Writing System Declaration
\par  Chapter 4 contains recommendations for in-file documentation
of electronic texts adequate to the bibliographic needs of
researchers, data archivists and librarians.  It recommends that
a special header be added to each file to perform a function
analogous to that of the title page of a non-electronic text, and
proposes sets of tags for information about the file itself, the
source from which it was derived and how it was encoded.
\par  Chapter 5, the largest chapter, attempts to define a set of
general-purpose structural and floating tags for continuous prose
texts.  Its basic idea of text as an ordered hierarchy of
objects, within which floating features and crystals may appear,
was discussed above.  This chapter of the Guidelines also
proposes tags for features such as lists, notes, names,
abbreviations, numbers, foreign or emphasised phrases, cross
references, and hypertextual links.  Sections deal with the kinds
of textual element commonly found in front and back matter of
printed texts, title pages etc. Other sections discuss ways of
encoding textual variation and critical apparatus and of
recording the rendering of arbitrary textual fragments within
this overall framework.  There is also some discussion of
different ways of maintaining multiple referencing schemes within
the same text.
\par  Chapter 6 outlines a number of theory-independent mechanisms
for representing all kinds of linguistic analyses of running
text.  It is probably the most daunting chapter for the
non-specialist reader, though much of its contents are of very
wide relevance.  It argues that most, if not all, linguistic
analyses can be represented as bundles of named, value-bearing,
`feature structures', which may be nested and grouped into sets
or lists.  It proposes ways of supporting multiple and
independently aligned analyses, chiefly by means of the ID/IDREF
pointer mechanism native to SGML.  It also contains some tagsets
for such commonly occurring formalisms as tree structures and
parts of speech.
\par  Chapter 7 considers in more detail particular aspects of some
specific types of text.  The text-types discussed in this draft
are: language corpora and collections; verse, drama, and
narrative; dictionaries; and office documents.  In each case, an
overview of the problems specific to these types of discourse is
given, with some preliminary proposals for tags appropriate to
them.  This chapter is one that will be considerably revised and
extended over the coming months, as its initial proposals are
firmed up and as its scope is extended to other types of text.
\par  Chapter 8 outlines a method by which the current Guidelines
may be modified and extended, largely by introducing indirection
into the document type definitions (DTDs) (the formal SGML
specifications for the TEI encoding scheme).  Extension and
modification of the TEI proposals is an important design goal,
since this is both expected and intended, and the final form of
the Guidelines will facilitate it.
\par  Preliminary versions of a number of technical appendixes are
provided in the current draft.  These include annotated examples,
illustrating the application of the TEI encoding scheme to a wide
range of texts, formal SGML DTDs for
all the tags and groups of tags defined in the TEI scheme, and
code pages for some commonly used character sets.  Later drafts
will extend and improve these initial versions considerably, and
will also contain an alphabetical reference section with a
summary of each tag, its attributes, its usage, and an example of
its use, as well as full Writing System Declarations for a range
of commonly used alphabets.
\par  Space precludes an exhaustive discussion of the various tags
and associated features suggested by the current TEI draft
proposals. Further proposals from the specialist working groups
currently discussing extensions in a wide range of subject areas
will be included in the final TEI report in a year's time.
However, it is hoped that enough detail has been provided to give
some indication of the general ideas underlying the scheme.
\end{document}
