hi vinmei
personally, i prefer free and easy tours because i like to walk with the locals along the streets, and i'm practically free to go anywhere and no time limit for sight seeing and no long bus rides.
Language may be a problem, but picking up some simple japanese like 'sumimasen' (means "excuse me" for hailing down locals for asking directions, or "Sorry" for accidents like bumping into people), 'arigato' (means Thank you) helps... usually the young japanese adults knows a bit of english, so is not too bad after all. In City areas, maps, road guides, train station names comes with english (or rather romanji), but if you wander off the city areas (like what me and hubby did who went to the outskirts), english is not a language to communicate as not many folks (esp the older generation) and sign boards will be able to help.
However, if you are really scared of getting lost and too shy to approach anybody for help, then, booking for a guided tour will be a better option.