As a student who has studied the Russian language, I'd suggest the Pocket Oxford Russian Dictionary, it is about 4" x 3" x 1" small to pack vinal covers, so fairly weather resistant, and well put together.
Arabic is a very difficult language, I haven't studied it, but I know of few phrasebooks that are said to be useful.
The Oxford Pocket Russian, has both Russian-English and English-Russian, as well as phonetic pronunciation of words in the cyrillic alphabet.
I have no idea about the political situation but for the pack weight, you have a good chance of being understood by someone, due to the russian occupation, if there is noone who speaks english. Before I spoke russian well I used my copy well in russia. This was in the early '90's where not many spoke english.
For anyone going there, goodluck and godspeed.
Edgedance (todd)