xxs ie xxs ie
xxs ie xxs ie ?
ɛ k s ɛ k s ɛ s WORD_BOUNDARY j eː WORD_BOUNDARY ɛ k s ɛ k s ɛ s WORD_BOUNDARY j eː WORD_BOUNDARY
x x s WORD_BOUNDARY i e WORD_BOUNDARY x x s WORD_BOUNDARY i e WORD_BOUNDARY