Normally, when you transfer a Pokémon from different language games, you don't get any recognition that they are from another country except for through their nickname. However, this is no longer true with Diamond & Pearl:

In Route 226, there is a house with a Hiker in. On the noticeboard there is a notice giving a list of Pokémon. These are all the Pokémon that have alternate Dex Entries. Now how do you get them you ask? Thats the easy part. There are actually several ways to obtain them;

  • Transfer them from your Different Language Game to a Japanese Game and upload them via Pal Park
  • Get one off of the Global Trading Centre
  • Trade for one with your friends, of whom did one of the above

The Pokémon that are affected by this cool new feature are as follows:

Ekans Pikachu Psyduck Ponyta Staryu Magikarp Wobbuffet
Heracross Sneasel Teddiursa Houndour Wingull Slakoth Roselia

Now once you have done this, when you go to the Pokédex entry for the Pokémon, on the bottom screen below the buttons to go previous or next will be an option for you to switch between different languages. These include Japanese, English, French, German, Spanish & Italian.
Just to give you a taster of this function. The hiker in the house will trade you his Magikarp for a Finneon. While it doesn't seem like a fair trade, his Magikarp is German and this gives you a perfect example of this new feature as seen to the right.