In response to this post: Quick Google Japanese Tip, a friend sent me this:

maybe these could help to use the Jp language setting for a search and then switch back to English
https://addons.mozilla.org/en-US/firefox/addon/743
https://addons.mozilla.org/en-US/firefox/addon/3863
https://addons.mozilla.org/en-US/firefox/addon/748
you could script a button or checkbox for your preferred language

Sounds like creating a macro would be a good way to get Google to behave better if you do a lot of Japanese only searches.