Dear xxx,
We have a great regard for the work that you have done in the research and information that you have provided here: (link)
It is well known that not everyone can read and understand English, so they look for blogs and information in their own language. We should like to translate your web page into Arabic, which, we believe, would be both informative and useful for your readers. People who understand Arabic will be able to read it and obtain benefit from it.
Please advise me of the best way to go about this.
Yours,
xxx
[Note: never say 'thanks', or anything similar, in a letter if you have not received anything.]