how to recognize similar words with difference in spelling

The Double Metaphone algorithm, published in 2000, is a new and improved version of the Soundex algorithm that was patented in 1918.

The article has links to Double Metaphone implementations in many languages.

The obvious, established (and well documented) algorithms for finding string similarity are:

Have a look at Soundex

There is a Soundex function in Transact-SQL (see http://msdn.microsoft.com/en-us/library/ms187384.aspx):

SELECT 
SOUNDEX('brook berta'),
SOUNDEX('Bruck Berta'),
SOUNDEX('Biruk Berta')

returns the same value B620 for each of the example values

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