Unless we know what it's for or failing that what you think should happen functionally, it would be rash to suggest any particular module or algorithm, If it's to correct typing errors, the "number of edits needed" is the most useful information. But if you want more statistical information, or if other factors play a part, you need to make very clear decisions (*) such as:-

- is order of the letters important, of weighted importance (and with what weighting), or irrelevant?

- are repeated letters important?

- should it be case-sensitive?

- are common dictionary variations or alternative parts of speech a close match?

- what part if any does soundex play in determining a match?

- is the match quotient intended to drive a hashing or other storage algorithm?

- etc. etc. etc.

I would not feel comfortable making any guess as to all those undeclared possibilities!

Update: * and of course post such clearer decisions in this thread.