Is children ' s laughter related to their language development ?

This paper aims at studying the acoustic development of child’s laughter and its relation to language acquisition. To our knowledge, the first study dealing with the acoustic proprieties of laughter is due to Habermann (1955). In this work, the author provided anemographic data and defines laughter as a reflexphenomenon with expiratory movements stopped by aspiratory pulses. Luchsinger and Arnold (1965) completed these findings using ultra-rapid imagery. They showed that laughter is characterized by a larynx in low position with expanded resonance cavities. As for its acoustic dimension, Trouvain (2003) defines laughter as a pattern of alternating non-voiced and voiced similar to a consonant-vowel syllable structure. Indeed, in the literature, laughter is often described along two segmental levels: a lower level, consisting of units that can be treated as consonants and vowels and a higher level that would be equivalent to the syllable (Bickley & Hunnicutt, 1992; Rothgänger et al., 1998; Apte, 1983; Provine, 1993, 2003; Savithri, 2000). Unfortunately, very few studies were conducted on children’s laughter (Nwokah et al., 1999; Mowrer, 1998; Tennis, 2009), while it first appears at about 4 months of age (Sroufe et Waters, 1976).