Thesis defense - Alex de Carvalho (LSCP): "The role of phrasal prosody and function words in the acquisition of word meanings"
September 15, 2017
At 2pm, room Dussane
Previous research demonstrates that having access to the syntactic structure of sentences helps children to discover the meaning of novel words. This implies that infants need to get access to aspects of syntactic structure before they know many words. Since in all the world’s languages the prosodic structure of a sentence correlates with its syntactic structure, and since function words/morphemes are useful to determine the syntactic category of words, infants might use phrasal prosody and function words to bootstrap their way into lexical and syntactic acquisition. In this thesis, I empirically investigated the role of phrasal prosody and function words to constrain syntactic analysis in young children (PART 1) and whether infants exploit this information to learn the meanings of novel words (PART 2).
In part 1, I constructed minimal pairs of sentences in French and in English, testing whether children exploit the relationship between syntactic and prosodic structures to drive their interpretation of noun-verb homophones. I demonstrated that preschoolers use phrasal prosody online to constrain their syntactic analysis. When listening to French sentences such as [La petite ferme][…–[The little farm][…, children interpreted ferme as a noun, but in sentences such as [La petite][ferme…] – [The little girl][closes…, they interpreted ferme as a verb (Chapter 3). This ability was also attested in English-learning preschoolers who listened to sentences such as ‘The baby flies…’: they used prosodic information to decide whether “flies” was a noun or a verb (Chapter 4). Importantly, in further studies I demonstrated that even infants around 20-months use phrasal prosody to recover syntactic structures and to predict the syntactic category of upcoming words (Chapter 5), an ability which would be extremely useful to discover the meaning of unknown words.
This is what I tested in part 2: whether the syntactic information obtained from phrasal prosody and function words could allow infants to constrain their acquisition of word meanings. A first series of studies relied on right-dislocated sentences containing a novel verb in French: [ili dase], [le bébéi] - ‘hei is dasing, the babyi’ (meaning ‘the baby is dasing’) which is minimally different from the transitive sentence [il dase le bébé] (he is dasing the baby). 28-month-olds were shown to exploit prosodic information to constrain their interpretation of the novel verb meaning (Chapter 6). In a second series of studies, I investigated whether phrasal prosody and function words constrain the acquisition of nouns and verbs. I used sentences like ‘Regarde la petite bamoule’, which can be produced either as [Regarde la petite bamoule!] - Look at the little bamoule!, where ‘bamoule’ is a noun, or as [Regarde], [la petite] [bamoule!] - Look, the little (one) is bamouling, where bamoule is a verb. 18-month-olds correctly parsed such sentences and attributed a noun or verb meaning to the critical word depending on its position within the syntactic-prosodic structure of the sentences (Chapter 7).
Taken together, these studies show that infants exploit function words and the prosodic structure of an utterance to recover the sentences’ syntactic structure, which in turn constrains the possible meaning of novel words. This powerful mechanism might be extremely useful for infants to construct a first-pass syntactic structure of spoken sentences even before they know the meanings of many words. Although prosodic information and functional elements can surface differently across languages, our studies suggest that this information may represent a universal and extremely useful tool for infants to access syntactic information through a surface analysis of the speech stream, and to bootstrap their way into language acquisition.