A B C D E F
a b c d e f .
a WORD_BOUNDARY b e WORD_BOUNDARY t̠ʃ e WORD_BOUNDARY d e WORD_BOUNDARY  e WORD_BOUNDARY  ə f WORD_BOUNDARY
a WORD_BOUNDARY b WORD_BOUNDARY c WORD_BOUNDARY d WORD_BOUNDARY e WORD_BOUNDARY f WORD_BOUNDARY