Most editions of the ds and ds lite support the same six languages. If you already own a ds lite from your country, just set the menu to Japanese.
There's also Chinese and Korean firmwares with minor differences.
Five region-locked carts were released for the ique ds. (the roms can be patched for a regular ds)
dsi and 3ds complicate matters. Depending on the model, the system languages available to ds games varies considerably.