When I launch XnView for the first time it is in English. I go to Tools->Options->Interface->Change language into Russian, it says you must restart XnView, but the language is changed immediately, without restart. However after restart it changes back to English. I've found that if I launch XnViewPortable.exe, change language and then restart - language stays in Russian(same thing when it starts after double click on some image). But when I launch it through portableapps.com platform it switches back to English. Please check this out.