Phonemic assimilation – bilabial place

De-alveolar assimilation is often highly predictable. So, if we know which particular alveolar occupies word-final position before the word boundary and the nature of the consonant occupying the word-initial position of the immediately following word, we can predict which phoneme will likely be substituted for the alveolar. We can, therefore, build rules that predict the nature of the assimilation that will take place. Consider the following rule.

This is probably best understood with an example. Consider the following phrase.

Here, the word-final sound of the word hit preceding the word boundary is the alveolar /t/. The sound in word-initial position in the word parade immediately following the word boundary is /p/. Consequently, according to our rule, the /t/ is realized as [p], i.e.

We notice, again, that the plosive [p̚] is unreleased. In fact, this is a common feature in clusters of plosives: here we have one /p/, in [hɪp], followed immediately by another /p/, in [pʰəɹeɪːd̥]. A further example should consolidate our understanding. Consider the following.

In this instance, the sound in word-final position of the word preceding the word boundary is the alveolar /t/ in the word fat. Further, the sound in word-initial position of the word boy that immediately follows the word boundary is /b/. Consequently, according to our rule, the /t/ should again be realized as /p/, i.e.

Further examples of the application of this particular rule include the following.

We see then how the alveolar plosive /t/ is substituted by the phoneme /p/ when it precedes a bilabial consonant. In summary, the alveolar plosive assimilates the place of articulation of the neighboring bilabial: the voiceless alveolar plosive is substituted by a voiceless bilabial plosive. We see from this that the transformed phoneme retains both the voicing (voiceless) and manner of articulation (plosive) of the alveolar sound for which it substitutes, it is only the place of articulation that is affected, i.e. it transforms from an alveolar into a bilabial. As one might expect, a similar rule applies to the voiced alveolar plosive /d/ when it precedes a bilabial. The following rule applies.

This rule is read in the same way as the previous rule, i.e.

‘If the sound in word-final position of the word preceding the word boundary is the alveolar /d/ and if the sound in word-initial position in the word immediately following the word boundary is either /p/, /b/, /m/ or /w/ then the /d/ will be realized as /b/.’

Consider the following phrase.

Here, the sound in word-final position of the word mad that precedes the word boundary is the alveolar /d/. Also, the sound in word-initial position in the word man immediately following the word boundary is /m/. Therefore, according to the rule the word-final /d/ will be realized as [b], i.e.

In this instance, the voiced alveolar plosive /d/ is substituted by the voiced bilabial plosive /b/. The affected alveolar therefore retains its voicing (voiced) and manner of articulation (plosive) but the place of articulation is transformed (from alveolar to bilabial). This should now make it quite clear as to why this process is known as de-alveolar assimilation, i.e. because the place of articulation is altered from alveolar. Here are some further examples of the rule that we are currently considering.

It should be apparent that, in each example, the alveolar /d/ is substituted this time by /b/ and not /p/. To reiterate, the voicing and manner of articulation of /d/ are retained but the place of articulation is affected, i.e. the voiced alveolar plosive is substituted by a voiced bilabial plosive. A third rule similarly applies to the alveolar nasal /n/, i.e.

Consider the following four examples of the application of this rule.

In each of these examples, the word-final /n/ of the word preceding the word boundary is immediately followed by a bilabial consonant. Under these conditions, the /n/ retains its voicing (voiced) and manner of articulation (nasal) but, again, the place of articulation is altered. In this case it assimilates the bilabial place of articulation of the immediately following bilabial sound. Hence, the voiced alveolar nasal /n/ is substituted by a voiced bilabial nasal /m/. It is apparent that the three rules described here operate when either an alveolar plosive or alveolar nasal precedes a bilabial across a word boundary. This may, therefore, be summarized diagrammatically as follows.

Alternatively this can be stated as follows.

Word-final /t, d, n/ become bilabial before bilabial consonants.

This assimilatory process operates when just one alveolar plosive or nasal appears word-finally. However, it continues to operate if clusters of the alveolar nasal and an alveolar consonant (i.e. /nt/ or /nd/) occur word-finally, and before a bilabial consonant across a word boundary. Under these circumstances, both sounds within the cluster assimilate the bilabial place of articulation:

A few examples should make this clear:

So, we can summarize this process with the following statement.

Word-final /nt, nd/ become bilabial before bilabial consonants.

NEXT>> Assimilation to Velar Place