All you have to do is to get latest NFE - Nokia cooker - phoenix then do the following steps :-

1) download the firmware that have the language you need
2) open the Rofs2 file from NFE then click on tools > Language Manager
3) click on "import/export languages" tab
4) select the language you want from the listed languages then click on export and save the file on your HDD
5) close this windows then open the other Rofs2 file from your CFW in NFE
5) open the extracted rofs2 folder from your HDD and open this file "resource\Bootdata\languages.txt"
6) edit the previous file and remove any spaces then save the file
7) click on "Reload from HDD" tab on NFE
click on tools > Language Manager then click on import and select the file you have previously exported
9) If everything went right then you should see your langauge in the drop down list on the first tap "Detect Languages".
10)you can delete whatever languages you do not need to save space on the C drive for your mobile
11) open the CFW rofs2 file from Nokia cooker and delete all folders from the program window
12) just drag and drop the files already extracted from NFE to nokia cooker then repack the files again
13) now flash your mobile with the newly created Rofs2 and the other files using phoenix.