The successful parent realizes that certain sounds in the English language are more difficult to pronounce than others. For example, the hard "C" sound can be particularly troublesome for the 2 y/o palate. Often the child will approximate the sound as best they can from the repertoire of sounds they have already mastered. For example, a 2 y/o might substitute a hard "T" sound for a hard "C" sound.
The successful parent realizes that to avoid discouraging a child from learning, it is important to maintain a straight face when this approximation makes for unfortunate mistakes in the pronunciation of words.
Even when the 2 y/o chases the cat around the house shouting, "Here "T"itty, "T"itty, "T"itty!"