[Nyororin]

I know this is probably not the type of answer you want... But...

If you do not speak Japanese, and are not really familiar with the language and it`s sounds - I highly suggest against giving a speech in Japanese. I would stick with giving the speech in English and then adding a word of congratulations in Japanese at the end. This will go over much more naturally and be appreciated by your friend and their family. If you were to give a long speech (which that would be for a language you do not know) you risk making terrible mistakes that can change meaning, embarrassing your friend, and making everyone else who doesn`t understand a bit uncomfortable.

If you do speak Japanese fairly well - put your attempt at a translation and you can get some help. Otherwise, really, I cannot express how uncomfortable this has the chance of making someone at a wedding.