hi guys just bought a 2011 Honda Odyssey and is a Japanese import. My question is can I change the software in the navigation to English?

That's a difficult one (but not impossible I'm sure) as it is a Japanese import and they were not designed to run anything other than domestic market language software.
An aftermarket audio system (double DIN if it fits) would be the best way forward as you can use Apps for SatNav and lots of other features the original unit would not have installed.