Allophonic assimilation – labialization
Within words, we have seen elsewhere that whenever the bilabial nasal /m/ or the alveolar nasal /n/ appears before a labiodental fricative /f, v/ they are likely to assimilate the labiodental place of articulation, e.g.
A similar process of allophonic assimilation can also across a word boundary. This pattern is summarized in the following rule.
This is read as:
‘If the sound in word-final position of the word preceding the word boundary is a nasal /m, n, ŋ/ and if the sound in word-initial position in the word immediately following the word boundary is a labiodental fricative /f, v/ then the nasal is labialized.’
Examples of this rule in operation include the following.
|home visit||/həʊm vɪzɪt/||→||[həʊ̃ːɱvɪzɪtʰ]|
|born free||/bɔn fri/||→||[bɔ̃ːɱfɹ̥ɪ]|
The assimilation of a bilabial or alveolar nasal before a labiodental fricative is reasonably common in connected speech. The assimilation of the velar nasal to a labiodental nasal in this context is, perhaps, less common but it is still possible to find examples in rapidly articulated speech, e.g.
|ring fence||/rɪŋ fɛns/||→||[ɹɪ̃ɱ fɛ̃ns]|
We can, therefore, summarize this rule with the following statement.
Word-final nasals are labialized before labiodental fricatives.
Another type of labialization occurs when labiodental fricatives occur in word-final position before a bilabial plosive, i.e.
The IPA symbol [ɸ] is used to represent the voiceless bilabial fricative, and [β] to represent the voiced bilabial fricative. These two phones have no contrastive function in English and they are, therefore, allophones of the corresponding phonemes /f/ and /v/. Examples of this process in action include the following.
|life peer||/laɪf pɪə/||→||[laɪɸ pʰɪəː]|
|live band||/laɪv bænd/||→||[laɪːβ bæ̃nd̥]|
Interestingly, this process does not occur within words in English but only across word boundaries in rapidly articulated connected speech. We can state this rule as follows.
Word-final labiodental fricatives are labialized before bilabial plosives.
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