his mother's father
his mother father
det:poss adj n
his mother's father.
h ɪ z WORD_BOUNDARY m ʌ ð ə ɹ z WORD_BOUNDARY f ɑ ð ə ɹ WORD_BOUNDARY
h i s WORD_BOUNDARY m o t h e r ' s WORD_BOUNDARY f a t h e r . WORD_BOUNDARY