7. Classification of English consonants according to the manner of articulation. Mistakes typical of Russian learners of English and way of correcting them

Modification of the place of obstruction and the active organs of speech: Assimilation may take place within a word and also at word boundaries. The following three important cases should be noticed:

(a) The alveolar allophones of [t, d, n, 1, s, z] are replaced by the dental variants when immediately followed by the interden­tal [ð] or [Ө], eg

within a word: eighth, breadth, tenth; at word boundaries: Put that down! Read this!, on the desk

(b)The post-alveolar [t] and [d] are heard before the post-alveolar sonorant [r], eg

within a word: trip, true, trunk, dream, drink; at word boundaries: at rest, would read.

(c)The bilabial nasal [m] or the alveolar nasal [n] become labio-dental under the influence of immediately following labio-­dental fricatives [f, v], eg

within a word: triumph, comfort, infant; at word boundaries: come for me, ten forks.