Consideration of Infants ’ Vocal Imitation Through Modeling Speech as Timbre-Based

Abstract. Infants acquire spoken language through hearing and imitat-ing utterances mainly from their parents [1,2,3] but never imitate their parents ’ voices as they are. What in the voices do the infants imitate? Due to poor phonological awareness, it is difficult for them to decode an input utterance into a string of small linguistic units like phonemes [3,4,5,6], so it is also difficult for them to convert the individual units into sounds with their mouths. What then do infants acoustically imitate? Develop-mental psychology claims that they extract the holistic sound pattern of an input word, called word Gestalt [3,4,5], and reproduce it with their mouths. We address the question “What is the acoustic definition of word Gestalt? ” [7] It has to be speaker-invariant because infants extract the same word Gestalt for a particular input word irrespective of the person speaking that word to them. Here, we aim to answer the above question by regarding speech as timbre-based melody that focuses on holistic and speaker-invariant contrastive features embedded in an utterance.