O (want) Sound Word List with the “a” Spelling
The /o/ sound has one alternative spelling, a, besides the usual o spelling. In some regions, many of the words on this list will be pronounced with an /aw/ sound distinct from the /o/ sound. In those regions, it is useful to try to pronounce them with an /o/ sound for spelling purposes.
Also for spelling purposes, words such as what and was on this list should be taught as having an /o/ sound rather than an /u/ or schwa sound. Just pronounce them with emphasis in a sentence to make the point.
Of the 7,000 words in the database constructed from a popular children’s dictionary, 42 of them are one-syllable words in which the vowel sound /o/ is spelled with an "a".