Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
CONSONANTS 1, THE AMERICAN ENGLISH
The consonants technically are both sounds and letters of the alphabet, and we use the term in both senses. The following table illustrates the American English consonant sounds initially, medially, and finally (note that not every consonant occurs in all three locations in the word, and note too that there can be several conventionally spelled representations of a given consonant sound, as for the f sound in fit, staff, laugh, cipher, and half).
Note that zh- does not occur initially in English words, although it does in French gendarme and the like. Note also that ng- does not occur initially in English words.
