Here is a tool that creates for every .nds file on your ds Card a .cc wich includes the language cheat.
This cheating tool actually only works with original Acekard Firmware NOT the AKAIO Firmware. I'll code a AKAIO version later.
The usage is very easy.
1. Download the "Language Cheat Creator for Acekard 2i" here.
2. Copy the "AK2iLanguageCheatCreator.nds" file to the root of your Micro SD Card
3. Start your DSi and the Acekard 2i
4. run AK2iLanguageCheatCreator.nds
5. Choose your favorite language and press 'A' to create the cheat files
6. Wait a while till you see "Finished.";
7. Restart your DSi and start Ak2i, enable cheats in Start -> Patches -> Cheat / Action Replay
8. Play all games in your language :)
If you find any bugs just tell me.