Similarity between two words I'm looking for a Python library that helps me identify the similarity between two words or sentences. 

I will be doing Audio to Text conversion which will result in an English dictionary or non dictionary word(s) ( This could be a Person or Company name) After that, I need to compare it to a known word or words. 

Example: 

1) Text to audio result: Thanks for calling America Expansion 
will be compared to American Express. 

Both sentences are somehow similar but not the same. 

Looks like I may need to look into how many chars they share. Any ideas will be great. Looks a functionality like Google search "did you mean" feature.
The closest would be like Jan has mentioned inhis answer, the Levenstein's distance (also popularly called the edit distance).


  In information theory and computer science, the Levenshtein distance
  is a string metric for measuring the difference between two sequences.
  Informally, the Levenshtein distance between two words is the minimum
  number of single-character edits (i.e. insertions, deletions or
  substitutions) required to change one word into the other.


It is a very commonly used metric for identifying similar words. Nltk already has an implementation for the edit distance metric, which can be invoked in the following way:

import nltk
nltk.edit_distance("humpty", "dumpty")


The above code would return 1, as only one letter is different between the two words.