Exercise 5, Grammar Development

For this exercise you can work with grammar4.lfg, which has integrated two OT-Marks to constrain PP-ambiguity. Alternatively, you can look at what has been added in grammar4.lfg and use it as a model while continuing work on your own grammar version.

Pronouns

• he sleeps.
• she devoured it.
• they devoured them.
• I waited for him for hours
• my dog sleeps
• she gave us her banana

Make sure the following sentences are rejected as ungrammatical (for the right reasons):

• him sleeps
• them devoured it
• they devoured they
• I waited for she for hours

For possessive pronouns you can use the following f-structure (here the example is for my):

SPEC [POSS [PRED 'I', NUM sg, PERS 1, PRON-TYPE poss]]

NB: Whenever you have to build a new phenomenon into your grammar and you are not sure how to analyze it, a good strategy is to look at the big ParGram grammars available via the INESS XLE Webinterface for guidance.

OT-Marks

The new grammar grammar4.lfg already contains two OT-Marks. They prefer local PP-attachment and choose an OBL analysis over an ADJUNCT analysis where there is a choice. This is fine for the most part, but causes problems elsewhere.

• However, the OT-Marks are not yet producing quite the right result. For example, in the first two examples below the OBL-AG reading is being ruled out. Get it back in and see if you can constrain the PP readings in some other way.
• For the examples with "wait" only the OBL readings are ruled in, but this is not right for "wait on/by the bench". Try to fix this. One way to fix things could be differentiate between animate and inanimate nouns. You could implement a generalization that if the object of the preposition is human, ([ANIM +]), then the OBL reading is licensed and if it is not inanimate ([ANIM -]), then the ADJUNCT reading is preferred.
• Your overall goal should be that all the sentences below get only one reading and only the right reading. If you cannot manage to make your grammar do that, write up a short report on why things did not work (sometimes things are just impossible to rule out within the syntax because lexical semantic information or world knowledge is needed).

1. the dog was given a bone by the girl
2. a bone was given to the dog by the girl
3. the gorilla waited on the bench
4. the zookeeper waited on the gorilla
5. the gorilla put the banana in the cage
6. the gorilla in the cage devoured a banana
7. the gorilla devoured a banana in the cage
8. a banana was put in the cage by the gorilla
9. the zookeeper waited by the bench
10. the zookeeper waited by the bench in the garden

Generator

Go through your testsuite and try to regenerate each sentence. Note down what your results are. When there should be only one possibility but there are more, think about whether and how you can fix it. If you can fix it (easily), then do so.

One possibility is to constrain some of the possibilities by using OT-Marks. If want to do this, then you can make up relevant OT-Marks and rank them on the hierarchy called GENOPTIMALITYORDER (already included in grammar4.lfg).

Relevant Reading Material

XLE Documentation on Support for Optimality Theory for information on how to use OT-Marks.

XLE Documentation on the generator.

XLE Documentation on the FS-Chart Window and packed representations.

Frank, Anette, Tracy Holloway King, Jonas Kuhn, und John T. Maxwell III. 1998. Optimality Theory Style Constraint Ranking in Large-scale LFG Grammars. Proceedings of the LFG 98 Conference. CSLI Online Publications.