Combinations of alveolar and interdental consonants with [r] [tr,dr,Or,6r].

In some of this clusters assimilation affecting the place and the manner of articulation can be observed. Thus under the influence of the post-alveolar [r] the alveolar consonants [t.d] in the clusters [tr,dr] become post-alveolar. The clusters [tr,dr] are actually characterized by double assimilation because the sonorant [r] is modified as well: under the influence of the noise consonants [t,d] it becomes fricative, and after [t], as was mentioned above,it is also devoiced.

In the clusters [Or,6r] the post-alveolar frictionless sound [r] is often replaced by an alveolar tap, or a flapped variety of [r]:a single brief tap is made by the tip of the tongue on the teethridge. In the cluster [O,6], besides, there is partial devoicing of the sonorant[r].

10)Absence of assimilation in some consonant clusters.

Clusters of alveolar and labio-dental fricatives with interdental sounds [s-O,z-6,s-6,6-s,O-z,f-6]and labiodentals fricatives with the bilabial sonorant [v-w,f-w] at syllable and word junctures present special difficulty for learners of English because they are only slightly different in articulation and perception and also because such contrasts as [v-w],[s-O]are not to be found in Russian or Belarusian. In pronouncing these clusters care should be taken to avoid assimilation according to the place or manner of articulation,i.e the quality of the adjacent sounds should be kept distinct.

11)Elision in consonant clusters.

Elision means the dropping of a sound or sounds, either within a word or at a junction of words. Elision is a feature of rapid colloquial speech, while formal speech tends to retain the full form of words under the influence of spelling.

One of the most typical examples of elision is the omission of[t] or [d] between two other consonants: friends[ ],mostly[   ].Another example is the elision of [h] in pronouns and auxiliaries. Pronouns with the initial [h] and the auxiliaries “have, has, had” commonly lose [h] when they are unstressed within utterance. [h] is pronounced in these words when they are initial in an utterance or when they are stressed: the people have gone[                ]. Clusters of two identical consonants at a word junction must not be redused by elision. The two consonants should be run together smoothly without a break: what time[      ],with this[       ].