csp101 badge

If an alveolar plosive or fricative appears word-finally, and is followed immediately by the post-alveolar approximant /j/, it will assimilate this post-alveolar place of articulation as follows:

assimilation of post-alveolar place process 1

Consider the phrase:

what you like /wɒt ju laɪk/

In a context such as this, the alveolar plosive /t/ at the end of the first word what is likely to assimilate the post-alveolar feature of the post-alveolar approximant /j/ that appears as the initial sound in the immediately following word you. It, therefore, becomes a post-alveolar affricate (assimilating the place of articulation of the /j/ whilst retaining its voicing and some of its plosive character):

what you like /wɒt ju laɪk/ [wɒʧ jə laɪkʰ][1]

An additional possibility here, especially in rapidly articulated connected speech, is that the post-alveolar approximant /j/ may be omitted altogether, i.e.

what you like /wɒt ju laɪk/ [wɒʧ ə laɪkʰ]

Further examples of this process include the following (the brackets around the (j) indicate that its inclusion is optional):

what you said /wɒt ju sɛd/ [wɒʧ (j)ə sɛd̥]
would you? /wʊd ju/ [wʊʤ (j)ə↓]
this year /ðɪs jɪə/ [ðɪʃ (j)ɪəː]
those years /ðəʊz jɪəz/ [ðəʊːʒ (j)ɪəːz̥]

We can state this rule as:

Word-final /t, d, s, z/ become post-alveolar before the post-alveolar approximant /j/, with possible disappearance of /j/.

In addition to the alveolar fricatives /s/ and /z/ becoming post-alveolar before /j/, they can also become post-alveolar before post-alveolar fricatives. However, recall that the voiced post-alveolar fricative /ʒ/ predominantly occurs between vowels and that there are very few words in English that have /ʒ/ in syllable-initial position. For the most part, therefore, /s/ and /z/ become post-alveolar when they occur before the voiceless post-alveolar fricative /ʃ/, which frequently occurs in syllable-initial position. This is summarized as follows:

assimilation of post-alveolar place process 2

Examples include:

this shop /ðɪs ʃɒp/ [ðɪʃ ʃɒpʰ]
those shoes /ðəʊz ʃuz/ [ðəʊːʒ̊ ʃuːz̥]

So, the complete rule for the assimilation of the alveolar fricatives to post-alveolars would be written as:

assimilation of post-alveolar place process 3

The following statement sums this up.

Word-final /s, z/ become post-alveolar before the voiceless post-alveolar fricative / ʃ/ and the post-alveolar approximant /j/, with possible disappearance of /j/.

NEXT>> Assimilation of Manner

[1] The substitution of the vowel /u/ in the word you with the neutral vowel [ə] is another example of vowel reduction which will be discussed later in this Section.