I don't know sweetheart
I do know
pro:sub mod v
i don't know sweetheart.
aɪ WORD_BOUNDARY d əʊ n tʰ WORD_BOUNDARY n əʊ WORD_BOUNDARY s w iː tʰ h ɑː tʰ WORD_BOUNDARY
i WORD_BOUNDARY d o n ' t WORD_BOUNDARY k n o w WORD_BOUNDARY s w e e t h e a r t . WORD_BOUNDARY