esas son las más difíciles
esas son las más difíciles .
e̞ s a s WORD_BOUNDARY s o̞ n WORD_BOUNDARY l a s WORD_BOUNDARY m a s WORD_BOUNDARY d i f i s i l e̞ s WORD_BOUNDARY
e s a s WORD_BOUNDARY s o n WORD_BOUNDARY l a s WORD_BOUNDARY m á s WORD_BOUNDARY d i f í c i l e s WORD_BOUNDARY . WORD_BOUNDARY