"Ivrit safa kasha" (Hebrew is a difficult language). This is the first sentence that most newcomers learn by heart when starting to learn Hebrew....
Hebrew (as well as Arabic) is a challenge to localizers. Not only do they have to deal with the translation, the Bi-Directional functionality takes its toll as well.
Some of the Hebrew related issues are:
Cultural Issues – Specific local references should be replaced with more appropriate or universal terms and graphics - for example most of the US sports metaphors are quite obscure to Hebrew or Arabic native speakers.
Text expansion - Text can often expand by more than 25% when translated into many European languages and about 30% when translated to Hebrew.
Date and time formats - Accepted time and date formats vary from country to country. In the US date display is mm/dd/yy while in Israel it is dd/mm/yy or dd/mm/yyyy. Same is true for measures and weights – converting from imperial to metric system, from ounces to grams, etc.
Hard-coded text and fonts - In software, hard-coded text strings cannot be translated and have to remain in English, which looks unprofessional. In Hebrew and Arabic, hard coded strings may cause problems during mirroring and flipping UI objects.
Multi-byte enabling - For Asian and Middle Eastern localization, software products must be Multi-byte enabling in order to support the character types used in these countries.