Editing Phoneme (section)

==Biuniqueness==
'''Biuniqueness''' is a requirement of classic [[structuralism (linguistics)|structuralist]] phonemics. It means that a given [[Phone (phonetics)|phone]], wherever it occurs, must unambiguously be assigned to one and only one phoneme. In other words, the mapping between phones and phonemes is required to be many-to-one rather than [[many-to-many]]. The notion of biuniqueness was controversial among some pre-[[generative linguistics|generative]] linguists and was prominently challenged by [[Morris Halle]] and [[Noam Chomsky]] in the late 1950s and early 1960s.

An example of the problems arising from the biuniqueness requirement is provided by the phenomenon of [[flapping]] in [[North American English]]. This may cause either {{IPA|/t/}} or {{IPA|/d/}} (in the appropriate environments) to be realized with the phone {{IPA|[ɾ]}} (an [[alveolar flap]]). For example, the same flap sound may be heard in the words ''hi'''tt'''ing'' and ''bi'''dd'''ing'', although it is intended to realize the phoneme {{IPA|/t/}} in the first word and {{IPA|/d/}} in the second. This appears to contradict biuniqueness.

For further discussion of such cases, see the next section.