I would like to think that if they exist, they can comprehend any language, not just Japanese. You'd think that all-powerful deities would be multilingual, right?
The Shinto "gods", such as they are, are a pretty inclusive bunch so they probably do. Plus, even if they didn't your ancestors have had plenty of time to teach them.
So feel free, have a chat. I'd point out that Shinto "gods" are not quite what you're probably thinking of when you use the word, but then, I take it from your question you aren't really super interested in a lesson in comparative theology are you?
Gods understand all the languages. The signal from the brain is the same for all languages (i.e) "Water / Au / ague" are different words in different languages but it means the same, the brain only think about the 'water' while we say. As gods have capacity to view the brain's signal they understand all the languages. If you have knowledge in parapsychology you can understand this easily. Some people don't believe in gods or deities but if they read their scriptures they can find the truth. Shinto gods are deities and can understand all the languages.
One thing to understand is that Kami aren't gods in the western sense of the word. Kami are spirits that temporarily reside in various objects. Shinto rituals always purify the place for the Kami, invite the Kami to descend, offer a meal, ask a favor, invite the Kami to depart. There is nothing that indicates a particular language must be used and you'll hear arguments for both sides.
More information is here: http://eos.kokugakuin.ac.jp/modules/xwords/category.php?categoryID=3
Do the shinto gods understand english?
