Syntactic category acquisition
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Syntactic category acquisition. Early words (Clark 2003). Early words (Clark 2003). people daddy, mommy, baby animals dog, kitty, bird, duck body parts eye, nose, ear food banana, juice, apple, cheese toys ball, balloon, book cloths shoe, sock, hat vehicles car, truck, boat

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Early words clark 20031
Early words (Clark 2003)

  • people daddy, mommy, baby

  • animals dog, kitty, bird, duck

  • body parts eye, nose, ear

  • food banana, juice, apple, cheese

  • toys ball, balloon, book

  • cloths shoe, sock, hat

  • vehicles car, truck, boat

  • household items bottle, keys, bath, spoon

  • routines bye, hi, uh oh, night-night, thank you, no

  • activities up, down, back

  • sound imitation woof, moo, ouch, baa baa, yum yum

  • deictics that



The meaning of syntactic categories
The meaning of syntactic categories verbs, and prepositions?

  • Nouns typically denote objects, persons, animals (nouns are non-relational and atemporal; Langacker)

  • Verbs typically denote events and states (verbs are relational and temporal; Langacker)


Cues for syntactic category acquisition
Cues for syntactic category acquisition verbs, and prepositions?

  • Semantic cues (Gentner 1982; Pinker 1984)

  • Pragmatic cues (Bruner 1975)

  • Phonological cues (Monaghan et al. 2005)

  • Distributional cues (Redington et al. 1998)


Maratsos and chalkely 1980
Maratsos and Chalkely (1980) verbs, and prepositions?

  • Nouns: the __, X-s

  • Verbs: will __, X-ing, X-ed,


Objections to distributional learning
Objections to distributional learning verbs, and prepositions?

  • ‘Noisy input data’

  • Det Adj __ P N ….

Syntactic categories are commonly defined in terms of their distribution; thus, it cannot be a surprise that distributional information is informative about syntactic category status. The argument is trivial or even circular.


Objections to distributional learning1
Objections to distributional learning verbs, and prepositions?

  • Distributional learning mechanisms do not search blindly for all possible relationships between linguistic items, i.e. the search is focused on specific distributional cues (Reddington et al. 1998).

The vast number of possible relationships that might be included in a distributional analysis is likely to overwhelm any distributional learning mechanism in a combinatorial explosion. (Pinker 1984)


Objections to distributional learning2
Objections to distributional learning verbs, and prepositions?

  • This assumption crucially relies on Pinker‘s particular view of grammar. If you take a construction grammar perspective, grammar (or syntax) is much more concrete (Redington et al. 1998).

The interesting properties of linguistic categories are abstract and such abstract properties cannot be detected in the input. (Pinker 1984)


Objections to distributional learning3
Objections to distributional learning verbs, and prepositions?

Even if the child is able to determine certain correlations between distributional regularities and syntactic categories, this information is of little use because there are so many different cross-linguistic correlations that the child wouldn’t know which ones are relevant in his/her language.(Pinker 1984)

  • Syntactic categories vary to some extent across languages (i.e. there are no fixed categories). Children recognize any distributional pattern regardless of the particular properties that categories in different languages may have (Redington et al. 1998)


Objections to distributional learning4
Objections to distributional learning verbs, and prepositions?

  • Children do not learn categories from isolated examples (Redington et al. 1998).

Spurious correlations will occur in the input that will be misguiding. For instance, if the child hears

John eats meat.

John eats slowly.

The meat is good.

He may erroneously infer The slowly is good is a possible English sentence.(Pinker 1984)


Redington et al 1998 data
Redington et al. 1998 - Data verbs, and prepositions?

All adult speakers of the CHILDES database (2.5 million words).

Bigram statistics:

Target words: 1000 most frequent words in the corpus

Context words: 150 most frequent words in the corpus

Context size:

2 words preceding + 2 words following the target word:

x the __ of x

in the __ x x

will have __ the x


Bigram statistics
Bigram statistics verbs, and prepositions?

Context vectors:

Target word 1 210-321-2-0

Target word 2 376-917-1-5

Target word 3 0-1-1078-1298

Target word 4 1-4-987-1398


Statistical analysis
Statistical analysis verbs, and prepositions?

  • Hierarchical cluster analysis over context vectors: dendogram

  • Treatment of polysemous words

  • ‘Slicing’ of the denogram

  • Comparison of the clusters of the dendogram to a ‘benchmark’ (Collins Cobuild lexical dictionary)


Syntactic category acquisition

Hierarchical cluster analysis verbs, and prepositions?


Syntactic category acquisition

Exp 1: Context size verbs, and prepositions?

Result:

Local contexts have the strongest effect, notably the word immediately preceding the target word is important.

"Learners might be innately biased towards considering only these local contexts, whether as a result of limited processing abilities (e.g. Elman 1993) or as a result of language specific representational bias." (Redington et al. 1998)


Syntactic category acquisition

Exp 2: Number of target words verbs, and prepositions?

Level of accuracy

Number of target words

Distributional learning is most efficient for high frequency open class words.


Syntactic category acquisition

Exp 3: Category type verbs, and prepositions?

Result:

nouns < verbs < function words

„Although content words are typically much less frequent, their context is relatively predictable … Because there are many more content words, the context of function words will be relatively amaophous." (Redington et al. 1998)


Syntactic category acquisition

Exp 4: Corpus size verbs, and prepositions?

Level of accuracy

Number of words


Syntactic category acquisition

Exp 5: Utterance boundaries verbs, and prepositions?

Result:

Including information about utterance boundaries did not improve the level of accurarcy.


Syntactic category acquisition

Exp 6: Frequency vs occurrence verbs, and prepositions?

‘Frequency vectors’ were replaced by ‘occurrence vectors’:

Frequency vector Occurrence vector

27-0-12-0-0-12-2 1-0-1-0-0-1-1

0-213-2-1-45-3-0 0-1-1-1-1-1-0

Result:

The cluster analysis still revealed significant clusters, but performance was much better when frequency information was included.


Syntactic category acquisition

Exp 7: Removing function words verbs, and prepositions?

Early child language includes very few function words. Thus, Redington et al. removed all function words from the context and repeated the cluster analysis without function words.

Result:

The results decreased but were still significant.


Syntactic category acquisition

Exp 8: Knowledge of word classes verbs, and prepositions?

The cluster analyses were performed over the distribution of individual items. It is conceivable that the child recognizes at some point discrete syntactic categories (cf. semantic bootstrapping), which may facilitate the categorization task.

Result:

Representing particular word classes through discrete category labels (e.g. N), does not improve the categorization of other categories (e.g. V).


Mintz et al 2002 cognitive science

Mintz et al. 2002. verbs, and prepositions?Cognitive Science

(1) The man [in the yellow car] …

(2) She [has not yet been] to NY.

  • 1. Information about phrasal boundaries improves performance.

  • 2. Local contexts have the strongest effect (cf. Redington et al. 1998).

  • 3. The results for Ns are better than the results for Vs (cf. Redington et al. 1998).


Monaghan et al 2005 cognition

Monaghan et al. 2005. verbs, and prepositions?Cognition

(1) Nouns vs. verbs

(2) Open class vs. closed class.

1. Distributional information

2. Phonological information


Syntactic category acquisition

Phonological features of syntactic categories verbs, and prepositions?

  • Length Open class words are longer than closed class words

  • Stress Closed class words usually do not carry stress

  • Stress Nouns tend to be more often trochaic than verbs (i.e. verbs are often iambic)

  • Consonants Closed class words have fewer consonant cluster

  • Reduced vowels Closed class words include a higher proportion of reduced vowels than open class words


Syntactic category acquisition

Phonological features of syntactic categories verbs, and prepositions?

  • Interdentals Closed class words are more likely to begin with an interdental fricative than open class words

  • Nasals Nouns are more likely than verbs to include nasals

  • Final voicing Nouns are more likely than verbs to end in a voiced consonant

  • Vowel position Nouns tend to include more back vowels than verbs

  • Vowel height The vowels of verbs tend to be higher than the vowels of verbs


Syntactic category acquisition

Results verbs, and prepositions?

Phonological features do not just reinforce distributional information, but seem to be especially powerful in domains in which distributional information is not so easily available.

  • Distributional information is especially useful for categorization of high frequency open class words.

  • Phonological information is more useful for catego-rization of low frequency open class words (Zipf 1935).

  • Phonological information is also useful for the distinction between open and closed class words.