Linguistic Modeling for Multilingual Machine Translation

Chapter 11
Lexical Functions
In the same way as MT systems havetoprovide a special treatment for function
words, a special treatment has to be developed for the cases where content
words do not have their habitual meaning but behave in a similar fashion to
function words. This is the case for the so-called lexical functions (LF) 1 .The
essence of the notion of the Lexical Function is that a word A selects a second
word B in order to realize a special syntactic or semantic structure related to
A, which is called the LF. Take Atobesmoker. In order to realize the high
degree of this concept, which is not possible by morphological operations for
English nouns, A selects B = heavy as its modier in order to realize through
the expression heavy smoker the high degree of smoker.
As functions cannot be translated into functions, A source but not B source can
be translated literally into another language. A literal translation of B source
could possibly result in a mismatch with the specication of B target found in the
A target .Thus, the Dutch harde storm (hard storm) is not correctly translated
as harter Sturm in German, although harde steen (hard stone) is a harter Stein
in German. Since the B for the LF Magnier for Sturm is schwer, harde storm
has to be translated as schwerer Sturm. Thus no translation rule of the type
hard=>schwer is involved in the translation of this example. In the same way
as in F-Structures, the total semantic value (e.g. the high degree) has to be
calculated in analysis, removing the marker (e.g. hard). The TL then has to
decide which function has to operate in order to express that meaning, with
1
The concept of Lexical Functions has been developed by Mel'cuk in the framework
of his Meaning,Text Model (cf. [Mel'cuk74], [Mel'cuk84], [Mel'cuk and Pertsov87],
[Mel'cuk88], [Apresjan91]). Since then the importance of this concept for purposes
of multilingual NLP has been more and more recognized (cf. [Magnusdottir88],
[Bloksma and van der Kraan91], [Heylen92], [Heylen et al.92]), which nallyresulted
in the integration of this concept in a number of MT systems (cf. [Apresjan et al.89],
[Apresjan et al.92a], [Heylen et al.93], [Streiter94], [Streiter95]).
111