localization testing is the testing of the system on which 
u r testing the s/w.

Localization testing checks how well the build has been 
translated into a particular target language. This test is 
based on the results of globalized testing where the 
functional support for that particular locale has already 
been verified.

Localization is the process of re-packaging
and re-engineering a product and software application and
their associated on-line help, readme, documentation, 
printed manuals, packaging and marketing collateral 
materials for a specific target language different from the 
market for which the product was originally developed, and 
ensuring that the functionality, usability and screen 
content is acceptable in the local culture