Based upon my experience with Dolphin 7, there's no mechanism to cache language files. Being that the "sys_localization_strings" and "sys_localization_keys" tables are 2 of the largest default tables, there should be an option to cache these or make them more efficient. It seems like these are being queried each and every time a page is loaded. If I have 1 language file on my system, I don't see any reason why these can't be cached.
