A new post in an old thread has pointed out that "bow" (/bəɷ/) and "bow" (/bɑɷ/) are homographs; it is interesting that "bough" (as in the branch of a tree - also /bɑɷ/) does not have the same pronunciation as the surname "Bough" (/bɔf/). So two spellings share three pronunciations.

This is probably not the best forum for making this observation, but I put it here for the interest of people following the old thread.