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\begin{document}
\begin{center}
{\LARGE \bf Integrating Morphology into the LKB}\\
ACQUILEX-II Working paper No.\ 17\\[5mm]
Bernie Jones\\
Computer Laboratory, University of Cambridge\\
{\tt Bernie.Jones@cl.cam.ac.uk}\\
August 1993
\end{center}


\section{Introduction}


The similarity between lexical processes, such as sense extension, and
morphological processes, such as nominalisation, has been noticed and
described in the literature for some time now [Copestake, 1992, Ch.~4]
[Briscoe \& Copestake, 1991]. Indeed, in relation to the {\sc Esprit
Acquilex} projects much has been made of this similarity, and the LKB
software is ideally suited to an implementation of these phenomena
through its lexical rule structure [Copestake \& Briscoe, 1991].
However, until now a major problem has been the lack of a mechanism
within the software to handle any form of morphographemic or
morphophonemic alternations. This has also been a problem from the
point of view of parsing, and associated with this the size of the
lexicon, since all morphological variants of every word need a
separate lexical entry if parsing is to succeed. This leads not only
to reduced performance due to an over-sized lexicon, but also failure
to capture the similarity in the variations between words, and the
extent to which morphological variants of the same word are related.

Of course the chief difficulty in designing a morphological component
to a system such as the LKB is that it is designed around
unification. It would be impossible to account for any modification to
the string value of the orthography feature of a feature structure
within a unification-based framework, so any system that is to perform
such a modification must work externally to the main LKB
algorithms. In uses of the LKB to date the problem has been tackled in
a rather unsatisfactory manner, due to the lack of any such external
morphology system. When orthographic modifications were desired, a
complex orthographic structure was created within the unification
mechanism, in which the components of the complex structure
corresponded to the individual morphemes. See for example the two
feature structures, and the lexical rules which created them, in
figures~\ref{teacher} and~\ref{rabbits}. These illustrate both the
derivational and inflectional applications of morphology.

\begin{figure}
\begin{center}
{\tiny
$\avmplus{\att{lex-noun-sign}\\
         \attval{ORTH}{\avmplus{\att{complex-orth}\\
                                    \attvaltyp{ORTH1}{teach}\\
                                    \attvaltyp{ORTH2}{er}}}\\
         \attvalshrunktyp{CAT}{noun-cat}\\
         \attvalshrunktyp{SEM}{obj-noun-formula}\\
         \attvalshrunktyp{QUALIA}{human}}$
}
\begin{verbatim}

              agentive
                 lexical-rule
                 < 1 > = strict-trans-sign
                 < 0 > = lex-noun-sign
                 < 0 : orth : orth1 > = < 1  : orth >
                 < 0 : orth : orth2 > = "er"
                 < 0 : qualia : telic > = < 1 : sem >
                 < 0 : qualia : telic : arg2 : arg1 : arg2 > =
                   < 0 : qualia : object-index >.

\end{verbatim}
\caption{Application of {\sc agentive} rule to {\it teach}}
\label{teacher}
\end{center}
\end{figure}

\begin{figure}
\begin{center}
{\tiny
$\avmplus{\att{lex-noun-sign}\\
         \attval{ORTH}{\avmplus{\att{complex-orth}\\
                  \attvaltyp{ORTH1}{rabbit}\\
                  \attvaltyp{ORTH2}{+s}}}\\
         \attvalshrunktyp{CAT}{noun-cat}\\
         \attval{SEM}{\avmplus{\att{obj-noun-formula}\\
                  \attval{IND}{\ind{0}}\avmplus{\att{obj}\\
                                       \attval{AGR}{\avmplus{\att{agr}\\
                                                \attvaltyp{NUM}{pl}\\}}}\\
                  \attvaltyp{PRED}{rabbit\_L\_1\_1}\\
                  \attval{ARG1}{\ind{0}}\\
                  \attvaltyp{PLMOD}{true}\\
                  \attvaltyp{QUANT}{false}}}\\
         \attvalshrunktyp{QUALIA}{nomqualia}}$
}
\begin{verbatim}


                plural
                    lexical-rule
                    < 1 > = lex-count-noun
                    < 1 : cat : m-feats : agr : num > = sg
                    < 0 : cat : m-feats : agr : num > = pl
                    < 0  > = lex-count-noun
                    < 0  : orth : orth1 > = < 1  : orth >
                    < 0  : orth : orth2 > = "+s"
                    < 1 : sem > = < 0  : sem >
                    < 1 : qualia > =  < 0 : qualia  >.

\end{verbatim}
\caption{Feature structure for {\it rabbits}, and {\sc plural} rule}
\label{rabbits}
\end{center}
\end{figure}


This paper describes the integration of an existing morphological
processing system with the current LKB, enabling proper orthographic
modification to take place in the full range of functions the LKB
offers.


\section{Morphology System}


The morphological analysis and generation system used here is a much
improved version of that first described in [Jones, 1991]. The system
works with a data structure created by compiling a set of
morphological rules based upon those in [Sanfilippo, 1990]. The
structure of the rules includes features such as name, and position
(suffix, prefix etc.), but most importantly a set of subrules in the
form of matched simple partial regular expressions. The first of each
pair of expressions will match a set of letters at the crucial site of
affix attachment in the stem (word-end, word-beginning, word-middle)
and the second expression describes the set of letters to replace them
with to form the morphologically complex form. Thus the following
might form a part of the past-tense rule in English:

\begin{verbatim}
        past-tense  suffix  (* ed) (e ed) (y ied) ...
\end{verbatim}

In this rule, the asterisk represents a null character, so that the
first sub-rule is the default ({\it e}d is added at the word-final
position). The rest of the sub-rules represent exceptions, so that if
e.g. the root form ends with {\it e} then that {\it e} is replaced by
{\it ed}. Since the final rules (see section~\ref{mrule}) are
structured in such a manner that the exception sub-rules override the
default, this prevents the formation of morphological complexes such
as {\it hateed}, or (since the ultimate example of an exception
sub-rule is one where a particular stem has a totally non-regular
complex form) {\it gived}.

This data is compiled into large, double rooted, double linked letter
trees --- one for each type of morphological attachment type (suffix,
prefix etc.), where the letters mark branches according to the
expressions in the rule. One half of the tree stores letter patterns
for the stem words, wheras the other half stores them for the
morphologically complex words; in effec,t therefore, one half of the
tree is for generation, and the other half is for analysis. A node in
one half of a tree may mark the position that a rule is triggered at
(that is, where the set of branches associated with the letters in a
particular sub-rule regular expression end) and contain links to the
other half of the tree. This point in the other half of the tree marks
the end of the branches corresponding to the other expression of the
pair in the morphological sub-rule.  Since the two halves of the tree
perform similar functions for both the first and last expressions in
each sub-rule, starting from either root node corresponds either to
generating a morphologically complex form, or analysing one down to a
stem. When using this data structure the word to be processed is
mapped character by character against the branches of the relevant
tree (starting from either one of the root nodes, depending on whether
generation or analysis is required). When a node is reached at which a
rule is triggered, the remainder of the word to be processed --- that
portion not matched by the regular expression in its translation to
the tree structure --- is kept, and characters from the other half of
the tree, from a pointer from the triggering node down to the other
root, are attached to it. Figure~\ref{prefix} illustrates some routes
that might be taken through the prefix tree when removing the {\it
en}({\it em}) prefix.

\begin{figure}
\begin{center}
$\odot \rightarrow e \rightarrow n \Longrightarrow \odot$

\bigskip

$\odot \rightarrow e \rightarrow m \rightarrow m \Longrightarrow 
m \rightarrow \odot$

\bigskip

$\odot \rightarrow e \rightarrow m \rightarrow b \Longrightarrow 
b \rightarrow \odot$

\bigskip

$\odot \rightarrow e \rightarrow m \rightarrow p \Longrightarrow 
p \rightarrow \odot$

\bigskip

\caption{Some possible analysis routes through the {\sc prefix} tree.}
\label{prefix}
\end{center}
\end{figure}

To actually perform the morphological analysis or generation, the data
trees are used repeatedly.  Obviously generation is the easier
operation, since it is known which rule is the appropriate one.  The
stem to be generated from is simply matched against the trees until a
node marked with the appropriate rule is found; then the link to the
other half of the relevant tree is followed and the morphologically
complex form is assembled. Analysis is a slightly more challenging
affair, in that it is perfectly possible for there to be not only
several different possible analyses of the same word, but also for
there to be multiple morphemes to strip from the word in order to
obtain the stem. Consider the word {\it unionise}, for example. There
are two possible analyses: either {\sc un+ion+ise} or {\sc union+ise},
both of which are perfectly valid\footnote{outside any context, that
is --- with context there will be a preferred interpretation
(pragmatically).}. Hence in the analysis software there is the
facility to maintain multiple possibilities for fragmentation, and
also to repeatedly analyse the resulting stems until no more breakdown
is possible\footnote{since only one morpheme at a time can be removed
from a word.}.

It is fortunate that the English language has relatively simple
morphology. Morphological modification seems to involve either
prefixation or suffixation rather than a combination of the two, and
infixation is very rare indeed. However, other languages are far more
rich. In German, for example, a single morphological step can often
involve both suffix and prefix addition, and in certain cases there is
also an infix change. See for example the past tense of the verb {\it
rennen}.

\begin{verbatim}
          renn-en  --->  ge-rann-t
\end{verbatim}

For this reason it is not enough simply to specify single place
morphological operations, as the original system described in [Jones,
91] did --- there should be the facility to link prefix, infix and
suffix operations together. The current system will permit this, and
although the rules will still be categorised into one of three
position types (prefix, suffix and infix), each rule can have
associated modifications for the other positions. This means that the
system becomes very modular and if there is some scheme that is
difficult to express in the current implementation (vowel harmony
might be, for example) then it is very simple indeed to add new
modules to the system to account for these phenomena. Hence this
morphological system is not only structurally very simple --- it is
also very powerful and flexible, which makes it ideal for the
integration with the LKB.


\section{Into the LKB}


Bearing in mind the similarity between the LKB's lexical rules and
the proposed morphological rules, it is likely that the morphological
variant will have to be included in all the places that the lexical
rules are used. The key functional locations are the following:


\subsection{Parsing}

It should be possible for words that are outside the LKB lexicon due
to morphological complexity to be included in a phrase for parsing,
and have feature structures built for these words from the lexical
entries of their stem morphemes. Thus the flexibility of the parser is
much enhanced, and the lexicon can be permitted to stay smaller. The
effect on the final parse should be much as the effect of the
application of lexical rules. That is that there should be an edge in
the chart for the result and argument of each rule that is applied
(morphological rules included). Thus if the phrase ``John sleeps'' is
to be parsed, both {\it sleep} and {\it sleeps} should appear in the
chart.


One problem that is raised by this is the interaction between
morphological and lexical rules. It is not possible, when analysing a
morphologically complex word, to first apply all the morphological
operations, and then apply all the lexical ones, or vice
versa. Consider the following examples:
\newpage

\begin{verbatim}

       sandwiches       (transfer of reference - human)
           |
       sandwiches       (plural)
           |
       sandwich         (root)



       beefs       (plural)
         |
       beef        (portioning)
         |
       beef        (root)

\end{verbatim}

In the first example, the morphological process of pluralisation is
applied to {\it sandwich}, followed by the transfer of reference rule
considered by [Nunberg, 1978]. He postulated that in the context of
waiters or waitresses talking in a restaurant, it would seem quite
natural to refer to a customer who has ordered a ham sandwich as {\it
the ham sandwich}. Therefore in this example the reference would be to
a customer who has ordered, say, a plate of sandwiches. In the second
example a lexical rule has transformed the mass term {\it beef} into a
count noun denoting a portion of that substance; this is then
pluralised.


It is therefore clear that lexical and morphological rule applications
must have the potential to be totally interleaved, so that they can be
applied in whichever order suits the unification constraints. This may
require the lexical rules to be formulated in a rather more strict
fashion to avoid over-generation, of course.


\subsection{Generation}


When the menu options to apply lexical rules to psorts are chosen in
the LKB menu, they should also have the ability to apply morphological
rules. Thus the option to apply a particular rule should check whether
that rule is morphological, and apply the appropriate orthographic
transformation on the resultant feature-structure given by the
unification procedure, and the function of applying all lexical rules
to a psort should exhibit similar behaviour. Obviously with the latter
possibility it should be possible to interleave application of
morphological and lexical rules when there is the possibility of
applying more than one rule to a psort.


\subsection{Translation}

In the same way that lexical rules are translated through the tlink
rule mechanism, morphological rules should have translation
equivalents in other languages so that correct translations can be
obtained if a morphologically complex form is to be translated --- that
is, the appropriate morphological rule is applied to the translation
of the stem-form of the complex word in the source language.

\bigskip

Therefore it seems that the best way to implement morphology in the
LKB is as a form of lexical rule. Indeed, the lexical rule mechanism
is admirably suited to that facet of the morphological manipulation
requiring default unification --- namely the specification of various
features in the syntax and semantics of the stem and final
forms\footnote{In the case of {\it plural} for instance, the argument
must be a singular count noun, and the result a plural one.}. A
morphological rule must how ever be distinctively different to a
lexical rule, so that it can be clearly distinguished as one. This is
obviously necessary so that the extra process of orthographic
modification can be implemented correctly.


\section{Implementation of LKB morphology}


Morphological rules are implemented in this system as a subtype of
lexical rule. Thus they are similar enough to lexical rules for
standard LKB unification operations to work, and yet distinctive
enough for the orthographic modification to be able to operate. The
morphological rules (whose structure is described in a later section)
are read in by the LKB twice: once by the lexical rules mechanism,
which deals with the information suitable for unification processing,
and once by a mechanism that uses a different section of the rules to
build the double rooted tree, described earlier, for use in the
generation/analysis stages.


Operations involving generation of morphologically complex forms are
accomplished in a fairly simple manner. The code is modified to
include a check for a morphological rule. If such a one is found, then
the unification function is called with an additional value for the
new orthography; if unification fails nothing happens, but if it is
successful the new orthography is inserted into the new feature
structure before it is returned to the calling function.


Parsing is a little more difficult since the interleaving of lexical
and morphological rules and possibility of many different stems must
be taken into consideration. Morphological analysis is attempted on
every word in the parse and the root morphemes and intermediate forms
(through morphological or lexical modification) are added to the
chart. Then if the word is also a valid lexical entry it is processed
normally; if not, then normal processing is inhibited, so that the
`word unknown' report is not generated. If, however, there are no
morphological possibilities for the word, then normal processing is
forced, whether the word is lexical or not. This is so that the
appropriate error message can be generated if the word does not occur
in the lexicon and is not the morphological complex of a lexical
stem.


\begin{figure}
\center
\setlength{\unitlength}{0.0100in}%
\begin{picture}(540,230)(85,465)
\footnotesize \thicklines \put(160,630){\line( 0,-1){ 20}} \put(160,650){\line( 4,
1){ 80}} \put(240,670){\line( 6,-1){120}} \put(280,610){\line( 4, 1){
80}} \put(280,590){\line( 0,-1){ 20}} \put(280,550){\line( 0,-1){ 20}}
\put(400,550){\line( 0,-1){ 20}} \put(560,550){\line( 0,-1){ 20}}
\put(560,510){\line( 0,-1){ 20}} \put(360,630){\line( 6,-1){120}}
\put(400,571){\line( 4, 1){ 80}} \put(480,592){\line( 4,-1){ 80}}
\put( 85,465){\framebox(540,230){}} 
\put(95,635){\makebox(0,0)[lb]{{REG-RAISED-NP-SIGN}}}
\put(225,675){\makebox(0,0)[lb]{{SIGN}}}
\put(215,595){\makebox(0,0)[lb]{{STRICT-TRANS-SIGN}}}
\put(215,555){\makebox(0,0)[lb]{{STRICT-TRANS-SIGN}}}
\put(465,595){\makebox(0,0)[lb]{{SIGN}}}
\put(345,635){\makebox(0,0)[lb]{{SIGN}}}
\put(370,555){\makebox(0,0)[lb]{{DET-SIGN}}}
\put(500,555){\makebox(0,0)[lb]{{LEX-COUNT-NOUN}}}
\put(500,515){\makebox(0,0)[lb]{{LEX-COUNT-NOUN}}}
\put(145,595){\makebox(0,0)[lb]{{Mary}}}
\put(270,515){\makebox(0,0)[lb]{{eat}}}
\put(395,515){\makebox(0,0)[lb]{{the}}}
\put(555,475){\makebox(0,0)[lb]{{nut}}}
\end{picture}
\caption{Parse tree for {\it Mary eats the nuts}}
\label{metntree}
\end{figure}

The morphological analysis is processed one step at a time, and
between each morpheme addition all possible combinations of lexical
rules are tried. All the resulting edges are stored in a temporary
list, the whole of which is added to the chart if and only if all rule
applications unify properly and there is a lexical entry for the stem
form. This does of course cause problems, since the subordinate edges
to the morphologically complex word in the parse only exist in a
theoretical sense within the structure of the parse. We have to make
sure that these edges cannot be picked up and spanned by rule
applications higher up in the parse. To ensure that this happens, the
subordinate edges are all made zero length, which means that they are
not considered by the rest of the parsing mechanism, but still appear
in the final output of the parse. So, for example, parsing ``Mary eats
the nuts'' results in the parse tree shown in figure~\ref{metntree}
and the feature structure shown in figure~\ref{metnfs} --- note the fact
that in the parse tree the orthography of the stem lexeme is given at
the leaf nodes. This reinforces the fact that they are a notional
component of the real parse.

\begin{figure}
\begin{center}
{\tiny
$\avmplus{\att{sign}\\
         \attval{ORTH}{\avmplus{\att{complex-orth}\\
                  \attvaltyp{ORTH1}{mary}\\
                  \attval{ORTH2}{\avmplus{\att{complex-orth}\\
                           \attvaltyp{ORTH1}{eats}\\
                           \attval{ORTH2}{\avmplus{\att{complex-orth}\\
                                    \attvaltyp{ORTH1}{the}\\
                                    \attvaltyp{ORTH2}{nuts}}}}}}}\\
         \attvalshrunktyp{CAT}{sent-cat}\\
         \attvalshrunktyp{SEM}{binary-formula}}$
}

\bigskip

\caption{Feature structure for {\it Mary eats the nuts}}
\label{metnfs}
\end{center}
\end{figure}

\section{Rule structure}

\label{mrule}

Since, by the description above, the same rule must be read twice by
two different input mechanisms, the two different sets of information
associated with each rule must each be hidden from the other. This is
easily accomplished through the use of a special character, which is
treated by the lexical rule input mechanism as a comment, yet
indicates to the morphological data compiler that the current line
contains information relevant to it. The following rule, for noun
pluralisation, illustrates this.

{\small
\begin{verbatim}

plural morph-rule
 %suffix (!s !ss) (!ss !ssses) (ss sses) (!ty !ties) (f ves) 
 % (tch tches) (sh shes) (person people) (man men) (formula formulae) 
 % (goose geese) (fish fish) (child children) (sheep sheep) 
 % (chicken chicken) (mouse mice) (louse lice)
   < 1 > = lex-count-noun 
   < 1 : cat : m-feats : agr : num > = sg
   < 0 : cat : m-feats : agr : num > = pl
   < 0 > = lex-count-noun 
   < 1 : sem > = < 0  : sem >
   < 1 : qualia > =  < 0 : qualia  >.

\end{verbatim}}

The portions following the \% sign at the start of the line form the
sub-rules relevant to the morphological compiler. The name of the rule
--- {\it plural} in this case --- is extracted from the header of each
rule.  The first word after the header --- {\it suffix} in this case
--- indicates which data structure to compile the current rule
into. The {\it !}  structure is used to denote special macro symbols
internal to the morphological system. Use and justification for these
is provided more fully in [Jones, 1991], but briefly they each expand
to a set of letters that could possibly replace them. These sets are
also defined in the file with the morphological rules, as follows:

\begin{verbatim}
     %(letter-set (!s abcdefghijklmnopqrtuvwxyz))
\end{verbatim}

They must, obviously, be defined prior to their first use in the rule
file, and only one particular macro symbol may be used in each
sub-rule.

Of course, this rule structure is slightly untidy, in that all the
exceptions to the productive morphological processes must be listed
explicitly. This has only been implemented in such a fashion for
the sake of simplicity, and since the testing lexicon in the LKB is rather
small. In a larger system one could envisage features for irregular
morphology being included in the lexical entries for stems. Hence the
presence of an irregular morphology for a particular rule would block
the application of that particular rule to the stem, and instead the
morphologically complex form would be taken from a feature in the
lexical entry.


\section{Conclusion}


\begin{figure}
\begin{center}
{\tiny
$\avm{\att{strict-trans-sign}\\
         \attvaltyp{ORTH}{enters}\\
         \attval{CAT}{\avm{\att{strict-trans-cat}\\
                  \attval{RESULT}{\avm{\att{strict-intrans-cat}\\
                           \attvalshrunktyp{RESULT}{sent-cat}\\
                           \attvaltyp{DIRECTION}{forward}\\
                           \attval{ACTIVE}{\avm{\att{np-sign}\\
                                    \attvaltyp{ORTH}{orth}\\
                                    \attval{CAT}{\avm{\att{np-cat}\\
                                             \attvaltyp{CAT-TYPE}{np}\\
                                             \attval{M-FEATS}{\avm{\att{nominal-m-feats}\\
                                                      \attvaltyp{REG-MORPH}{boolean}\\
                                                      \attval{AGR}{\avm{\att{agr}\\
                                                               \attvaltyp{PERS}{3}\\
                                                               \attvaltyp{NUM}{sg}\\
                                                               \attvaltyp{GENDER}{gender}}}\\
                                                      \attvaltyp{NOMINAL-FORM}{nominal-form}\\
                                                      \attvaltyp{CASE}{case}\\
                                                      \attvaltyp{COUNT}{boolean}}}}}\\
                                    \attval{SEM}{\ind{0}}\ \ \boxvaluebold{p-agt-formula}}}}}\\
                  \attvaltyp{DIRECTION}{backward}\\
                  \attvalshrunktyp{ACTIVE}{dir-obj-np-sign}}}\\
         \attvalshrunktyp{SEM}{strict-trans-sem}\\
         \attvalshrunktyp{SENSE-ID}{sem-sense-id}}$
}
\caption{3rd person present tense form of {\it enter}}
\label{enters}
\end{center}
\end{figure}

\begin{figure}
\begin{center}
{\tiny
$\avmplus{\att{lex-count-noun}\\
         \attvaltyp{ORTH}{lammen}\\
         \attval{CAT}{\avmplus{\att{noun-cat}\\
                  \attvaltyp{CAT-TYPE}{n}\\
                  \attval{M-FEATS}{\avmplus{\att{nominal-m-feats}\\
                           \attvaltyp{REG-MORPH}{boolean}\\
                           \attval{AGR}{\avmplus{\att{agr}\\
                                    \attvaltyp{PERS}{person}\\
                                    \attvaltyp{NUM}{pl}\\
                                    \attvaltyp{GENDER}{gender}}}\\
                           \attvaltyp{NOMINAL-FORM}{nominal-form}\\
                           \attvaltyp{CASE}{case}\\
                           \attvaltyp{COUNT}{true}}}}}\\
         \attvalshrunktyp{SEM}{unary-formula-entity-arg1}\\
         \attval{SENSE-ID}{\avmplus{\att{sense-id}\\
                  \attval{FS-ID}{\ind{0}}\ \ \myvaluebold{lam\_1}\\
                  \attvaltyp{LANGUAGE}{dutch}\\
                  \attvaltyp{DICTIONARY}{string}\\
                  \attvaltyp{LDB-ENTRY-NO}{string}\\
                  \attvaltyp{HOMONYM-NO}{string}\\
                  \attvaltyp{WORD}{string}\\
                  \attvaltyp{SENSE-NO}{string}}}\\
         \attvalshrunktyp{QUALIA}{animal}}$
}
\caption{{\it Lambs} translated into Dutch through the {\sc tlink-rule} mechanism}
\label{lammen}
\end{center}
\end{figure}


The morphological system integrates well with the LKB, and enhances
its functionality. Examples with the parsing function have already
been shown in the previous section, and examples of use in the other
two functions amount to little more than the display of some feature
structures. The structures corresponding to the application of the
3rd-person-singular rule to the verb {\it enter}, and the translation
of the plural of {\it lamb} into Dutch are given in
figures~\ref{enters} and~\ref{lammen} respectively. In the latter
example we are linking the English and Dutch plural formation rules
trough the translation link mechanism --- this seems the logical
manner in which to do morphology in translation.

The system performs to specification, allowing a full range of
inflectional and derivational morphological phenomena to be
experimented with within the LKB. Also, as mentioned previously, the
system is not difficult to extend in order to cope with different
morphological phenomena that have not been catered for in the current
implementation.


In the current system, there is no facility to tackle compounding
phenomena, unless a specific rule is written for each compound --- one
could, for example, envisage the rule in figure~\ref{vlees} being
written to cope with the animal grinding phenomenon in Dutch, and the
figure also shows a feature structure of the translation of {\it
chicken} (meat) into Dutch using this rule, via a translation rule
linking the English {\sc animal-grinding} rule to the Dutch {\sc
vleescompounding} one. This is very important since it illustrates
just how closely morphological and lexical rules are related, since
the translation link rule in this case is between a lexical and
morphological rule, rather than between two rules of the same type.


\begin{figure}
\begin{center}
{\tiny
$\avmplus{\att{lex-noun-sign}\\
         \attvaltyp{ORTH}{kippevlees}\\
         \attvalshrunktyp{CAT}{noun-cat}\\
         \attvalshrunktyp{SEM}{unary-formula-entity-arg1}\\
         \attvalshrunktyp{SENSE-ID}{sense-id}\\
         \attval{QUALIA}{\avmplus{\att{c\_natural}\\
                  \attvalshrunktyp{AGENTIVE}{agentivestuff}\\
                  \attvalshrunktyp{TELIC}{verb-sem}\\
                  \attval{FORM}{\avmplus{\att{nomform}\\
                           \attvaltyp{RELATIVE}{mass}}}\\
                  \attvalshrunktyp{CONSTITUENCY}{nomconst}\\
                  \attval{OBJECT-INDEX}{\ind{0}}\ \ \myvaluebold{entity}\\
                  \attvalshrunktyp{PROPERTIES}{phys-properties}}}}$
}
\begin{verbatim}

               vleescompounding morph-rule
               %suffix (p ppevlees) (m mvlees)
                    < 1 : sense-id : language > = Dutch
                    < 1 : qualia > = animal
                    < 1 : cat : m-feats : agr : num > = sg
                    < 0 : qualia : form : relative > = mass 
                    < 0 : qualia > = c_natural .

\end{verbatim}
\caption{An illustration of the Dutch version of {\it animal-grinding}}
\label{vlees}
\end{center}
\end{figure}     

\newpage

\section{References}

\leftmargin 1.6em
\parindent -\leftmargin

:

{\bf Briscoe, E J \& Copestake, A}, 1991, {\it Sense Extensions as
Lexical Rules}, Acquilex Working Paper No. 22, in {\bf Sanfilippo, A} (Ed),
{\it The (Other) Cambridge Acquilex Papers}, Cambridge University
Computer Laboratory Technical Report No. 253

\bigskip

{\bf Copestake, A}, 1992, {\it The Representation of Lexical
Semantic Information}, Sussex University Cognitive Science Research
Paper No. 280

\bigskip

{\bf Copestake, A \& Briscoe, E J}, 1991, {\it Lexical Operations in
a Unification-based Framework}, Acquilex Working Paper No. 21, in {\bf
Sanfilippo, A} (Ed), {\it The (Other) Cambridge Acquilex Papers},
Cambridge University Computer Laboratory Technical Report No. 253

\bigskip

{\bf Jones, B E M}, 1991, {\it A Morphological Analyser}, Cambridge
University Computer Laboratory Part II Dissertation

\bigskip

{\bf Nunberg, G D}, 1978, {\it The Pragmatics of Reference}, PhD
thesis, University of California, reproduced by the Indiana University
Linguistics Club

\bigskip

{\bf Sanfilippo, A}, 1990, {\it A Morphological Analyser for English
and Italian}, Acquilex Working Paper No. 4, in {\bf Sanfilippo, A}
(Ed), {\it The (Other) Cambridge Acquilex Papers}, Cambridge
University Computer Laboratory Technical Report No. 253

\end{document}

