Well i didn't know that Monster Racers (U) have the language in Spanish. Well you could download the Monster Racer (U) again and try it. Hope that helps
What flashcart/emulator do you use ? I don't think it's the game's problem, might be the DS/Emulator's. Check here for help on language http://forum.romulation.net/index.php?topic=1462.0
Go to settings and change the language to English? Post Merge: [time]1274689278[/time] Game language is not English, even though I downloaded the (U),(E) version etc. FLASHCART: Install English firmware. If multilanguage etc., it automatically sets the language accordingly to your firmware language. Make sure to have your flashcart firmware English as well. Some ROMs contain other languages even if it's specified it only contains a certain language (Japanese containing English for example), these usually can be brought out with a code enabled. In some cases, an (E) ROM will not contain English. EMULATORS: If emulators such as no$gba, it's because by default, the BIOS firmware language isn't set as English. If multilanguage etc., it automatically sets the language accordingly to your firmware language. Easy solution is to simply download the English DS firmware.bin and have the file in the same directory of no$gba. Another method, get any NDS ROM. And then change your settings so you load the BIOS (GBA BIOS in settings), and then save settings and reset. And then while you're in the DS firmware, go to settings and change the language to English. Save the DS settings, change back to load cartridge directly and then save no$gba's settings. And then load the game. Should work. Copied directly from http://forum.romulation.net/index.php?topic=1462.0 to help you.
Ah, no$gba user aren't you ? Then use this full package http://www.mediafire.com/download.php?0tmrvozm0gm