overlapping (n.)

A term used in PHONOLOGY to refer to the possibility that a PHONE may be assigned to more than one PHONEME (phonemic overlapping). The notion was introduced by American STRUCTURAL LINGUISTS in the 1940s. The overlapping (or ‘intersection’) of phonemes was said to be ‘partial’ if a given sound is assigned to phoneme A in one PHONETIC CONTEXT and to phoneme B in another; it would be ‘complete’ if successive occurrences of the sound in the same context are assigned sometimes to A, and sometimes to B (compare the notion of NEUTRALIZATION). An example of partial overlap is found between /r/ and /t/ in some DIALECTS of English, where both are realized by the TAP  in different contexts: /r/ ⇒  after DENTAL FRICATIVES, as in through; /t/ ⇒  between VOWELS, as in bitter. An example of complete overlap occurs in the case of , which may stand for most occurrences of English STRESSED vowels, when they occur in unstressed positions (e.g. telegraph – telegraphy, where the first and third vowels reduce to ).

The notion of complete overlap was generally rejected, on the grounds that it would lead to an unacceptable INDETERMINACY in phonemics which would destroy the principle of phonemic analysis as an independent LEVEL. One would not be able to tell, on the basis of pronunciation alone, which phoneme a phone belonged to. The need to preserve some kind of phonemic integrity for successive instances of the same sound led to the maxim ‘Once a phoneme, always a phoneme’, and to the notion of BIUNIQUENESS (or one-to-one correspondence between phones and phonemes). However, even partial overlap provides considerable difficulties for the notion of INVARIANCE, which is fundamental to the biuniqueness hypothesis, as has been argued by Noam Chomsky, among others. It is evident that it is not always possible to predict the phoneme a phone belongs to, simply by considering its phonetic properties.

A term used in early language ACQUISITION studies to refer to one type of relationship between adult and child MEANING, as expressed in LEXICAL ITEMS. Overlapping meanings, or overlap, as the name suggests, occur when the meaning of a lexical item for the child is not identical with that for the adult. In cases of no overlap (‘mismatch’), a child’s lexical item has no point of contact at all with the meaning of that item in the adult language, e.g. one child used door to mean ‘walk’. The term is now of largely historical interest.