Hi Abdullah. Please feel free to contact me if you need to translate into Persian (Farsi)

The translation part is the easiest part and it is done (both the forward and backward), the challenging parts which came thereafter!

To validate a translation you have to make a pilot study with a representative sample. It would be necessary do a item analysis using IRT (the model depends of the kind of item you have). And you have to do a DIF analysis as well.

Thanks all,

What do you think about this guidelines?

http://www.ncbi.nlm.nih.gov/pubmed/11124735

If you cannot open it, I can send you a copy

Here is a nice summarizing article: http://www.saudija.org/article.asp?issn=1658-354X;year=2017;volume=11;issue=5;spage=80;epage=89;aulast=Tsang

And here is a special related issue: http://www.saudija.org/currentissue.asp?sabs=n