ASSIMILATION SUMMARY

Assimilation is something which varies in extent according to speaking rate and style; it is more likely to be found in rapid, casual speech and less likely in slow, careful speech. 

We have two types of assimilation:

As an example, consider a case where two words are combined, the first of which ends with a single final consonant (which we will call Cf) and the second of which starts with a single initial consonant (which we will call Ci); we can construct a diagram like this:

-   -  -  -  Cf  |  Ci  -  -  -  -                                                                                        

             word

          boundary

1) REGRESSIVE:

-   -  -  -  Cf  |  Ci  -  -  -  -                                                                                                  

If Cf changes to become like Ci in some way, the assimilation is called regressive (the phoneme that comes first is affected by the one that comes after it).

2) PROGRESSIVE:

-   -  -  -  Cf  |  Ci  -  -  -  

If Ci changes to become like Cf in some way, the assimilation is called progressive. 

Now, the main differences between consonants are of three types, so we can identify:

i) Assimilation of place of articulation

ii) Assimilation of manner of articulation

iii) Assimilation of voicing.

Assimilation of place is most clearly observable in some cases where a final consonant (Cf) with a place of articulation that is not alveolar. For example: in rapid, casual speech the t will become p before a bilabial consonant, as in: 

‘that person’ /ðæp pɜːsņ/                                                                                   

 ‘light blue’  /laɪp bluː/                                                                                                            

‘meat pie’  /miːp paɪ/

Before a dental consonant, t will change to a dental plosive, for which the symbol is t, as in: 

‘that thing’ /ðæt θɪŋ/                                                                                                      

‘get those’ /ɡet ðəʊz/                                                                                                 

‘cut through’ /kʌt θruː/

Before a velar consonant, the t will become k, as in: 

‘that case’ /ðæk keɪs/                                                                                               

‘bright colour’ /braɪk kʌlə/                                                                                           

‘quite good’ /kwaɪk ɡʊd/

In similar contexts d would become b, d and g, respectively, and n would become m, n and ŋ. 

However, the same is not true of other alveolar consonants: s and z behave differently, the only noticeable change being that s becomes ʃ, and z becomes ʒ when followed by ʃ or j, as in: 

‘this shoe’ / ðɪʃ ʃuː/                                                                                              

‘those years’ /ðəʊʒ jɪəz/

Assimilation of manner is much less noticeable, and is only found in the most rapid and casual speech; generally speaking, the tendency is again for regressive assimilation.  

It is thus possible to find cases where a final plosive becomes a fricative or nasal:

‘that side’ /ðæs saɪd/              

‘good night’ /ɡʊn naɪt/

But most unlikely that a final fricative or nasal would become a plosive. 

In one particular case we find progressive assimilation of manner, when a word-initial ð follows a plosive or nasal at the end of a preceding word. For example:

‘in the’ ɪn ðə ---------->   ɪnnə                                                                

‘get them’ ɡetðəm ------>   ɡet təm                                                                   

‘read these’ riːd ðiːz ------>   riːd diːz

It seems that the ð phoneme frequently occurs with no discernible friction noise.

Assimilation of voice is also found, but again only in a limited way. Only regressive assimilation of voice is found across word boundaries, and then only of one type.

If Cf is a lenis (“voiced”) consonant and Ci is fortis (“voiceless”) we often find that lenis consonant has no voicing; this is not very noticeable case of assimilation, since, initial and final lenis consonants usually have little or no voicing anyway. 

When Cf is fortis (“voiceless”) and Ci lenis (“voiced”), a context in which in many languages Cf would become voiced, assimilation of voice never  takes place; for example: 

‘I like that black dog’ /aɪ laɪk ðæt blæk dɒɡ/. 

It is typical of many foreign learners of English to allow regressive assimilation of voicing to change the final k of ‘like’ to ɡ, the final t of ‘that’ to d and the final k of ‘black’ to ɡ. 

If in a syllable-final consonant cluster a nasal consonant precedes a plosive or a fricative in the same morpheme, the place of articulation of nasal is always determined by the place of articulation of other consonant; thus: 

‘bump’ /bʌmp/

‘tenth’ /tenθ/  

‘hunt’ /hʌnt/    

‘bank’ /bæŋk/

It could be said that this assimilation had become “fixed” as part of the phonological structure of English syllables. 

A similar example of type of assimilation that has become fixed is the progressive assimilation of voice with the suffixes s and z; thus:

‘cats’  /kæts/          ‘dogs’/dɒɡz/

‘jumps’/dʒʌmps/   ‘runs’/rʌnz/

‘Pat’s’/pæts/          ‘Pam’s’ /pæmz/