Answer: sandhi

AnswerCrossword Clue
SANDHISound modification
sandhia process of phonetic modification
sandhimorphophonemic alternation, esp. as determined by phonetic environment, as in dontcha for don't you
sandhimodification of the sound of a morpheme (as a word or affix) conditioned by syntactic context in which it is uttered (as pronunciation of -ed as d in glazed and as in paced or occurrence of a in a cow and of an in an old cow)