1. 1 Human simulations of vocabulary learning Présentation Interface Syntaxe-Psycholinguistique Y-Lan BOUREAU Gillette, Gleitman, Gleitman, Lederer

2. 2 Outline Some background The problem to be solved Facts : nouns’ acquisition precedes verbs’ acquisition Existing theory Gillette et al.’s hypothesis Simulation experiment Learning from observation Learning from linguistic hints Discussion

3. 3 The problem of language learning Children learn language from scratch Traditional hypothesis : Children hear adults speak They spot that « cat » is uttered most frequently when there is a cat around They infer that « cat » means ‘cat’ But babies’ vocabulary does not reflect input frequencies much more nouns than verbs in babies vocabulary

4. 4 Nouns are learnt earlier A conceptual hypothesis : Verbs are conceptually more difficult So cannot be learnt until babies display adequate conceptual knowledge Alternative hypothesis : information requirements Verbs require some syntax to be already acquired (e.g. : I know that Mommy is coming )

5. 5 Pairing word to world Three sources of information : Nonlinguistic evidence (e.g. Mommy says « cat » when the cat is there) Linguistic evidence : Co-occurrence of semantically related words in sentences (e.g. food names usually appear with verbs like « eat ») Syntactic structures in which words occur (e.g. a verb with one subject and two complements is likely to be of the « give » kind)

6. 6 Hypothesis Hypothesis : the baby (1) acquires a small stock of nouns by word-to- world pairing (2) uses that stock of nouns as a scaffold for constructing representations of the linguistic input that will support a more efficient learning procedure Support : correlation of changes in vocabulary size with appearance of multiword speech

7. 7 A simulation experiment Principle : Adult learners (no conceptual issues any more) Trying to guess : most frequently used nouns or verbs Observational clues : video clips Linguistic clues : co-occurring words, syntactic frame

8. 8 First experiment Only videoclips Adults trying to guess 24 nouns and 24 verbs

9. 9 Results, Part I : Nouns win Nouns are guessed with much better results than verbs :

10. 10 Imageability rules Provided clues are exclusively visual Nouns of the set (e.g. elephant, plane, bag) are a lot more « imageable » than verbs (e.g. think, know, wait)

11. 11 Results, part II Nouns Verbs Nouns

12. 12 Conclusion of experiment I The one relevant factor seems to be imageability Not that surprising : from a video, you learn imageable things ; a thing that is not imageable would be hard to picture !!

13. 13 Linguistic clues vs. Observational clues All nouns removed. 6 conditions : 1 : videoclips (but with a bip for the verb) 2 : alphabetical lists of nouns 3 : 1+2 (videoclips + alphabetical lists) 4 : syntactic frames with all nonsense words 5 : sentences with only the verb as nonsense 6 : 1+5 (videoclips + sentences)

14. 14 Linguistic clues vs. Observational clues

15. 15 Linguistic clues vs. Observational clues 6 conditions : 1 : videoclips (but with a bip for the verb) 2 : alphabetical lists of nouns 3 : 1+2 (videoclips + alphabetical lists) 4 : syntactic frames with all nonsense words 5 : sentences with only the verb as nonsense 6 : 1+5 (videoclips + sentences)

16. 16 Results No nouns provided !! No more visual information !! Nouns reintroduced Visuals reintroduced

17. 17 Linguistic clues vs. Observational clues Remarkably : leap between 3 and 4, whereas the reverse could have been expected ! Interestingly, those verbs that were best learnt in the observational learnings show a decrease between 3 and 4

18. 18 Discussion Verbs : complementary distributions (12 never learnt with visual clues = 12 best learnt with linguistic clues) This distribution corresponds to the « imageability » criterion : Quite logically, you can learn visually only what is visually representable Verbs that use higher level linguistic representations have to wait until those can be constructed

19. 19 Discussion : general scheme First, imageable words are learnt on a word-to-world pairing basis Those imageable words are mostly nouns That would explain why nouns make up most of young infants’ vocabulary Second, this first set of words allows learning of new words on a sentence-to- world pairing Thus conceptual words can be learnt as well

20. 20 Some reservations The argument structure is the same across languages (logical requirements), but : Adults already know the words, so they could try to guess the verbs by exhaustive search with all the information given (e.g. : the best performance is for « look », and it is probably due to the use of « look » with « at » )

21. 21 The End