abrir abre la boca
abrir abre la boca .
a β ɾ i ɾ WORD_BOUNDARY a β ɾ e̞ WORD_BOUNDARY l a WORD_BOUNDARY β o̞ k a WORD_BOUNDARY
a b r i r WORD_BOUNDARY a b r e WORD_BOUNDARY l a WORD_BOUNDARY b o c a WORD_BOUNDARY . WORD_BOUNDARY