depends where you are going... when i first moved there i only spoke the basics and being in a town of under 10,000 most things were in japanese and i fumbled my way through it. in the cities most things are in english too. As said below they do speak a bit of english and they do thrive on being complimented on it. some ppl are shy and pretend they cant speak english too. nowadays i speak and read enough to get by with most things
tl:dr
youll have no problems, they are friendly and will help you out