The class of approximants: its members, its parameters, and its history.

The object of this study is to give a modern definition of an approximant. Definitions given by dictionaries are at first reminded. Then an inventory of the members of the class is made. Voiceless approximants, according to Catford (1977) and descriptions of languages, are considered as members of the class. Phonetic (articulatory, acoustic, and auditory) previously given parameters of the members of the class are reminded. A list of phonologic features permitting to oppose approximants to other classes of sounds, given between 1950 and 1990 are reminded, in particular, Williamson (1977)’s multivalued [stricture] and Clements (1990)’s [approximant] feature. After a recall of the origin of the class and of the name, a survey of what was proposed before as a definition of an approximant is done in the third part. It appears that the class may contain only voiced central oral consonants or, at the contrary, all voiced and voiceless vowels, plus all voiced and voiceless central oral consonants. As a conclusion, a definition is chosen.