phonological patterns STRUT, FOOT

StAmE does not share the British tendency to raise the vowel of strut towards  (this vowel is represented with [ə] in ODP). However, StAmE has a long history of alternation of the vowel in roof, root (but not foot) as , with the short vowel more common in the North. The same is true, through with [u] in the North and  in the South, for coop. Route is another word with alternation, this time commonly between [u] and . These alternations do not apply across the entire word class of  words, although there is some evidence that there used to be more words that showed the alternation (e.g. gums).