By the GBA era, encoding for characters in names has become standardized. You can freely trade between games in different languages from then on without issue, except in a few cases:
- If you're trying to connect with the GameCube games Colosseum or XD, or the Wii games Pokemon Battle Revolution or My Pokemon Ranch, those can only communicate with cartridges that match the disc's own language
- If you're trying to send Pokemon to Pal Park (generation 3->4 transfer), the games in both slots must be the same language, or it won't be able to transfer. Note that the special modified encounters in certain routes with dual-slot mode are usable even if the GBA game is a different language.
- If you're trying to use Poke Transfer (generation 4->5 transfer), the special DS Download Play title that gets transmitted to facilitate the moving of Pokemon will only detect Sinnoh/Johto games that are the same language as the Unova game that requested the transfer.
All later transfers can be done regardless of language. Starting in the DS era, where wi-fi trading was originally instituted as an expected feature, there's even a bonus for trading with a player in a different language: while traded Pokemon normally get 50% bonus experience, that bonus increases to 70% if the Pokemon comes from a different-language game, and if you take that Pokemon to the day care to get eggs, the chance of getting Shiny Pokemon is increased.
