I don't believe it
I do believe it
pro:sub mod v pro:per
i don't believe it.
aɪ WORD_BOUNDARY d əʊ n tʰ WORD_BOUNDARY b ɪ l iː v WORD_BOUNDARY ɪ tʰ WORD_BOUNDARY
i WORD_BOUNDARY d o n ' t WORD_BOUNDARY b e l i e v e WORD_BOUNDARY i t . WORD_BOUNDARY