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: When the flow speeds up, it can dig the river bottom, causing further erosion. 
Sentence2: when a river flows faster, it will create a deeper valley due to increased erosion.

erosion