You just need to download the English menu folder and override your current language file with an English language file.
http://www.modpiiri.com/asennusohjeet/dstt/dstt117.zip TTDS English v.1.17 MENU
To answr this question you must be specific. You can not say THE language because there are many different languages.
you don't translate the cheats you update them i no a website were you can download them http:/cheats.gbatemp.net
If you want to play gba games on a ttds then you need a gba emulator compatible for the ttds but i don't think there is one.
ds hobro
Yes.
nope
You can get them off the internet, just search buy ttds. Also it depends where you live but there might be some shops around that sell them
go to amazon.com
Yes, TTDS / R4DS are illegal, but ONLY if you use them for "ROM"s. You can apparently use them for other kinds of media, like music.
Download .sav file, make it exatly same name as the ROM you want the save file.Then just play.Sorry for my crappy English
No they can not go into dsi XL or dsi. There is a possibility that the system will break. But there is a dsi or dsi XL TTDS like chips.