Exercise 9, Grammar Development

Adding a Finite-State Morphological Analyzer


In this exercise, you will practice integrating a morphological analyzer into your grammar. Up to date, you have been working with a full form lexicon. This means you have full control over the lexical entries within your grammar, but it is also very tedious as you have to write a separate lexical entry for each inflected (or derived) form.

In this exercise we will work with a version of the finite-state morphological analyzer that is part of the English ParGram grammar. It is called english.infl.patch.full.fst and can be found in the "prelex" folder of the English ParGram grammar. The English ParGram grammar is available to you freely via the XLE license.

Alternatively, you can also build your own finite-state morphological analyzer and hook it up, or use a different type of analyzer altogether. Details as to the morphology-grammar interface can be found in the Starter Notes and in the XLE Morphology Section.

You can use grammar9.lfg as a model. We have already integrated verbs together in this file in classe. You. will also need morph-lex.lfg, morph-rules.lfg, MCONFIG.lfg.

Extending the Grammar: Nouns and Adjectives

grammar9.lfg already interacts with the morphological analyzer with respect to verbs.

Now expand the grammar so that nouns and adjectives are also coming out of the morphological analyzer.

Generally proceed in the following way:

  1. grammar9.lfg already has the morph-lex.lfg and morph-rules.lfg files integrated unter "FILES" in the configuration file and the headings (MORPH ENGLISH) have been added in "LEXENTRIES" and "RULES". This needs to be done to ensure that the new files are indeed considered part of the grammar. Note also that all the relevant files (morph-lex-.lfg, morph-rules.lfg and MCONFIG.lfg) need to be in the same directory as the grammar (or you can specify the paths to where they are).
  2. In this exercise, we are working with a morphological analyzer that is a "black box" for us. That is, we know what the input is, but we don't know the inner workings of the morphological analyzer. In order to see what the output of the morphological analyzer is from within XLE, type "morphemes some-word". For example:
    % morphemes bananas
    analyzing {bananas}
    {bananas "+Token"|banana "+Noun"  "+Pl"}
  3. If this works, it is a sign that the morphological analyzer is part of the grammar.
  4. The "morphemes" command shows oen what the output of the morphological analyzer is. Use this knowledge to integrate the relevant information into the grammar.
    1. Make sure you have an entry for all the tags that are produced as output in morph-lex.lfg, i.e., "+Noun" and "+Pl" in the example above. If not, add the missing ones in.
    2. Decide what functional information you want associated with any given tag. Where possible, use existing templates from your grammar.
    3. You can also decide to have no information associated with a tag, for example: "+Verb V-POS XLE ."
    4. Now write sublexical rules that can parse all the tags in the right order (morph-rules.lfg).
    You should make sure that the following sentences work, with the nouns and the verbs coming from the morphological analyzer:



    Remember to keep thinking and working on your projects.

    Please submit your exericses and your testsuite to Maike Müller (uni konstanz Addresse) by 31.6.2014 at 10 am.

    Relevant Reading Material

    The Grammar Writer's Cookbook, Ch. 12

    Kaplan, Ron, John T. Maxwell III, Tracy Holloway King and Richard Crouch. 2004. Integrating Finite-state Technology with Deep LFG Grammars. In Proceedings of the ESSLLI04 Workshop on Combining Shallow and Deep Processing for NLP.

    Starter Notes

    XLE Morphology Section