Speech rhythm and pitch patterns in Bengali: Implications for prosodic acquisition.

Abstract

Rhythmic timing, measured as durational variability of consonantal and vocalic intervals, is thought to be a cue for phonological chunking in infant acquisition [Ramus et al. (1999)], i.e., for learning stress‐timing (English) versus syllable‐timing (Spanish). Another source of rhythm that has been less studied in infant speech development is “macrorhythm” in pitch contours, regularity in f0 marking of prosodic structure [Jun (2005)]: Head‐marking languages with variable contours on each word (English) are distinguished from edge‐marking languages with a recurring pattern on each word (Korean). Bengali is a language with a moderately constrained syllable structure, and both head‐ and edge‐marking: weak stress and a recurring rise on each content word [Khan, (in press)]. To explore how Bengali can be best categorized in terms of rhythmic timing and macrorhythm, and how speakers may adjust these properties to aid infant language acquisition, we analyzed various durational and intonational measurements in recordings of ten speakers reading a passage in both laboratory speech and simulated infant‐directed speech (IDS) styles. Preliminary results suggest that while Bengali has syllable timing and strong macrorhythm, speakers do not highlight these rhythmic properties in IDS, but instead counteract them by increasing consonantal interval variability and interrupting the regular rising f0 patterns.