Fusion (phonetics)

In phonetics and historical linguistics, fusion, or coalescence, is a sound change where two or more segments with distinctive features merge into a single segment. This can occur both on consonants and in vowels. A word like educate is one that may exhibit fusion, e.g. /ɛdjʊkeɪt/ or /ˈɛdʒʊkeɪt/. A merger between two segments can also occur between word boundaries, an example being the phrase got ya being pronounced like gotcha /ɡɒtʃə/. Most cases of fusion lead to allophonic variation, though some sequences of segments may lead to wholly distinct phonemes. A common form of fusion is found in the development of nasal vowels, which frequently become phonemic when final nasal consonants are lost from a language. This occurred in French and Portuguese. Compare the French words un vin blanc [œ̃ vɛ̃ blɑ̃] "a white wine" with their English cognates, one, wine, blank, which retain the n's. Often the resulting sound has the place of articulation of one of the source sounds and the manner of articulation of the other, as in Malay. Vowel coalescence is extremely common. The resulting vowel is often long, and either between the two original vowels in vowel space, as in [ai] → [eː] → [e] and [au] → [oː] → [o] in French (compare English day [deɪ] and law [lɔː]), in Hindi (with [ɛː], [ɔː]), and in some varieties of Arabic; or combines features of the vowels, as in [ui] → [yː] → [y] and [oi] → [øː] → [ø]. Compensatory lengthening may be considered an extreme form of fusion. Historically, the alveolar plosives and fricatives have fused with /j/, in a process referred to as yod coalescence. Words like nature and omission have had such consonant clusters, being pronounced like /naːˈtiu̯r/ and /ɔˈmisjən/. Words ending in the Latin-derived suffixes -tion and -sion, such as fiction and mission, are examples that exhibit yod coalescence. This sound change was not, however, distributed evenly. Words like module may be realised as either /ˈmɒdjuːl/ or /ˈmɒdʒuːl/. Words that did not experience universal yod coalescence, are always realised as two segments in accents like Received Pronunciation.