I'm not sure why
I not sure why
pro:sub neg adj pro:rel
i'm not sure why .
aɪ m WORD_BOUNDARY n ɑ t WORD_BOUNDARY ʃ ʊ ɹ WORD_BOUNDARY w aɪ WORD_BOUNDARY
i ' m WORD_BOUNDARY n o t WORD_BOUNDARY s u r e WORD_BOUNDARY w h y WORD_BOUNDARY