Is there an algorithm that lets you find the word-level edit distance between 2 sentences? For eg., "A Big Fat Dog" and "The Big House with the Fat Dog" have 1 substitute, 3 insertions
You can use the same algorithms that are used for finding edit distance in strings to find edit distances in sentences. You can think of a sentence as a string drawn from an alphabet where each character is a word in the English language (assuming that spaces are used to mark where one "character" starts and the next ends). Any standard algorithm for computing edit distance, such as the standard dynamic programming approach for computing Levenshtein distance, can be adapted to solve this problem.