Special speech registers: talking to australian and Thai infants, and to pets

Infant directed speech (IDS) is the special speech register used to talk to human infants. This paper provides an historical and theoretical background to the study of IDS and special speech registers, as an introduction to four papers which follow. These are concerned with Australian IDS [2], Thai IDS [3,4], and Australian pet directed speech (PDS) [5]. 1. Infant Directed Speech A Brief History Humans use special speech registers for a variety of purposes: when talking to young infants, to foreigners, to hearingimpaired listeners, to people who are ill, to lovers, and to pets, just to name a few. One of the most extensively studied of these registers is the speech directed to young children and infants (infant directed speech and child directed speech IDS, and CDS respectively). Systematic study of speech directed to children began mainly as a reaction to claims made by Chomsky made regarding language acquisition and the language acquisition device (LAD) [6]. Part of the argument for an LAD was that the linguistic input to the young child (and linguistic input generally) is not well formed grammatically, i.e., it is impoverished. This led researchers such as Snow, Gleitman and Cross to conduct extensive studies on the nature of the speech input to young children [see 7]. Almost invariably these early studies were conducted on speech to children of language-producing age, because the primary purpose was to investigate how linguistic input might be unconsciously tuned to the level of the linguistic development of the child [8,9]. These studies also tended to concentrate on the syntactic and semantic aspects of this speech style. More recently, with the upsurge in studies concerned with preverbal infants’ perception of language, studies of infantas opposed to child -directed speech have proliferated [see e.g., 10,11]. In these, due to the age of the addressee, the emphasis has shifted from the linguistic (syntactic and semantic) aspects of speech to its acoustic and phonetic qualities, with especial emphasis on the prosodic nature of IDS. Other studies have also looked at the affective qualities of IDS [12]. 2. The Role of Infant Directed Speech On the basis of these studies, it appears that IDS has at least three roles: to engage infants’ attention, to express and elicit positive affect, and to teach infants about aspects of the ambient language. If these are universal roles in IDS, then they should be evident in all languages. A good test of this hypothesis is to investigate these roles in quite disparate languages, e.g., English and Thai. In addition, if there are unique aspects of infant directed speech, which are unique because the recipient is a human capable of producing language, then IDS should differ from pet directed speech (PDS) in just those speech characteristics which carry the didactic/linguistic information. There are four papers in this series. These are concerned with the acoustic and affective characteristics of infant-directed speech to Australian English language infants [2], the acoustic characteristics of infant-directed speech to Thai language infants [3], the pragmatic characteristics of infant-directed speech to Thai language infants [4] and finally the acoustic, phonetic, and affective characteristics of pet-directed speech [5]. Through consideration of these cross-language, crossregister, and cross-species studies, the nature and purpose of IDS will be elucidated.