bu ne bak bu ne
bu ne bak bu ne ?
b ʊ WORD_BOUNDARY n ɛ WORD_BOUNDARY b a k WORD_BOUNDARY b ʊ WORD_BOUNDARY n ɛ WORD_BOUNDARY
b u WORD_BOUNDARY n e WORD_BOUNDARY b a k WORD_BOUNDARY b u WORD_BOUNDARY n e WORD_BOUNDARY