Allophonic assimilation – de-voicing of liquids
We know that the liquids /r, l/ are prone to being de-voiced in single words when they occur after voiceless consonants. This process can also function across a word boundary in connected speech. So, if a word-final voiceless consonant precedes a word-initial liquid across a word boundary, the liquid will be de-voiced, i.e.
Consider the following.
|Miss Wright||/mɪs raɪt/|
The sound immediately preceding the word boundary is the word-final voiceless consonant /s/ of the first word Miss. This is followed immediately after the word boundary by the word-initial liquid consonant /r/ of the second word Wright. In this instance, it is the sound before the word boundary that affects the sound following the word boundary. Consequently, it is the liquid /r/ that assimilates the voicing of the preceding voiceless consonant, becoming de-voiced, i.e.
|Miss Wright||/mɪs raɪt/||→||[mɪ̃s ɹ̥aɪːʔ]|
We see, therefore, that this is an example of so-called left-to-right assimilation, as the sound to the left of the word boundary affects the sound to the right of the word boundary. Further examples of left-to-right de-voicing in which a voiceless consonant precedes a liquid include the following.
|hot love||/hɒt lʌv/||→||[hɒt̚ l̥ʌv̥]|
|hip length||/hɪp lɛŋθ/||→||[hɪpʰ l̥ɛ̃ŋθ]|
|bike race||/baɪk reɪs/||→||[baɪkʰ ɹ̥eɪs]|
In each of these examples it is the liquid sound, either /l/ or /r/, in word-initial position immediately following the word boundary, that is assimilated. In each case the liquid assumes the voicing of the preceding voiceless consonant and is de-voiced. We can state this rule as:
Word-initial /l, r/ are de-voiced after voiceless consonants.