I would say to keep the original language for a couple reasons. On is because of international/ interdojo use. If 5 people translate something, you get 5 different answers.
Secondly (bear in mind I train in Japan), my aikido teacher acutally doesn't care for the names at all. He says that they focus too much on a part of the move. (like someone stated before, calling the kote-gaeshi a 'wrist twist' focuses too much on the last and least important part of the move). If we tried to translate everything, I think that we'd have a fragemented understanding of what is going on. Techniques (I think) need to be viewed as a whole, not just the flash at the end. If we changed irimi-nage to something like "aiki-clothesline" then I think a lot of what makes the technique work/important would get lost. As far as ikkyo through gokkyo- would learning them as techniques 1-5 really help?