Definition: Generate an overlapping word between the given two sentences. When you find the overlapping words, they don't have to match exactly, e.g., "survival" and "survive" are valid overlapping words. Little words like "the" or "of" don't count! You must generate significant words which are not the stop words.
Input: Sentence1: Sound waves are an example of longitudinal waves. 
Sentence2: the type of material through which a longitudinal wave passes changes the speed at which a longitudinal wave travels.

longitudinal