bilabial (adj./n.)

A term in the classification of CONSONANT sounds on the basis of their PLACE OF ARTICULATION: it refers to a sound made by the coming together of both lips. Examples are the initial sounds in pin, bin, mat; a non-English bilabial would be the initial sound in Welsh mhen ‘my head’. The term is restricted to consonantal ARTICULATION; the active use of the lips in the articulation of VOWELS is discussed in terms of ROUNDING and SPREADING. The only common speech sounds in which a single lip is the primary articulator are known as LABIO-DENTALS. ‘Monolabial’ is not found as a technical term; ‘quadrilabial’ exists only in humour, as part of the PHONETICIAN’S technical description of a kiss!