Sensitivity to prosody in different modalities: how specific are the mechanisms involved in language acquisition?
In past work, we have proposed that a specific version of the Iambic-Trochaic Law (ITL) at the phrasal level offers a cue to the relative order of heads and complements, both cross-linguistically and within one language (Nespor, Shukla, van de Vijver, Avesani, Schraudolf & Donati 2008). Given the sensitivity of infants to prosody, we also suggested that the ITL could lead infants to the acquisition of the basic word order of their language of exposure. In this talk, I will present experiments that show that adult participants group sequences of syllables that vary either in duration or in pitch as predicted by ITL. Results showing that infants are sensitive to pitch but not duration distinctions at 7 months (Bion, Benavides & Nespor 2011), while they are sensitive to both at 9 months (Hay & Saffran 2012) will also be discussed. A version of the ITL has first been proposed to account for grouping in music (Bolton 1894; Woodrow, 1951): it is thus not exclusively a linguistic grouping mechanism, but more generally it accounts for the grouping of auditory stimuli. I will present results that show that the ITL can account for grouping also in the visual domain (Peña, Bion & Nespor 2011) and that while the rhythm of the native language can influence grouping in linguistic stimuli, it does not influence grouping in other domains (Langus, Seyed-Allaei, Uysal, Pirmoradian, Toro, Peña, Bion & Nespor, under revision). Finally, I will present results of recent experiments that show that prosody is also detectable in the spontaneous gestures that accompany speech production (Guellaï, Langus and Nespor, 2014), as well as in lip movements (Peña, Langus and Nespor, under review). Conclusions will be drawn about the nature of the mechanisms involved in language acquisition.