On the day of the show, I sit down with someone that speaks very good English and someone who speaks the local language very well and work out what I'm going to say.
To be honest, I couldn't hold a conversation with anybody in any language other than English - and that's a struggle sometimes!
Believe it or not, Japanese is actually easier than some European languages!
I do that in whatever language of the country I'm in, because the audience appreciate it.