A cross-cultural comparison of tonal synchrony and pitch imitation in the vocal dialogs of Belgian Flemish-speaking and Mexican Spanish-speaking mother-infant dyads

This study reports a cross-cultural comparison of the vocal pitch patterns of 15 Mexican Spanish-speaking and 15 Belgian Flemish-speaking dyads, recorded during 5. min of free-play in a laboratory setting. Both cultures have a tradition of dyadic face-to-face interaction but differ in language origins (i.e., Romanic versus Germanic). In total, 374 Mexican and 558 Flemish vocal exchanges were identified, analyzed and compared for their incidence of tonal synchrony (harmonic/pentatonic series), non-tonal synchrony (with/without imitations) and pitch and/or interval imitations. The main findings revealed that dyads in both cultures rely on tonal synchrony using similar pitch ratios and timing patterns. However, there were significant differences in the infants' vocal pitch imitation behavior. Additional video-analyzes on the contingency patterns involved in pitch imitation showed a cross-cultural difference in the maternal selective reinforcement of pitch imitation. The results are interpreted with regard to linguistic, developmental and cultural aspects and the 'musilanguage' model.