dorothy sayers, in the introduction to her translation of inferno, defending english from the charge of being "poor in rhyme:"

"...it is remarkably rich in vowel-sounds. of these, italian possesses seven only, all "pure" and unmodified by the succeeding consonants. for english, on the other hand, the shorter o.e.d. lists no fewer than fifty-two native varieties, shading into one another by imperceptible degrees. this phenomenon result from the fact that most english vowels are dipthongs to start with and nearly all are subtly modified by a following consonant, particularly by a following 'r.' indeed, in southern english, this self-effacing consonant when it appears at the end of a word seems to exist for the sole purpose of performing this duty to its vowel, dying without a murmur when its work is done, after the manner of certain male spiders. (in northern english and in the celtic dialects the 'r' is more tenacious of life.)"