There is no such tool, sorry. While the way a NDS ROM is packed is the same with every ROM, the way the files are packed inside are not. Each game is different and in many cases, each game requires its own tools to extract the data from it. Thats why to translate a game, more often than not you need a programming background to make tools to extract and unpack language files.
Well a general program is not possible but for each specific game it can be done. That is what loadingNOW did for pokemon. If you made a mistake, you can ask for help (at the thread you made on translating diamond).