I am going on a vacation to Japan this summer for a week. What are some good places to visit?

My family and I will be going to Japan for a short week long mini vacation on our way back from our main vacation in Vietnam. What I would like to know is that, what are some good places to visit in Japan for a week? What customs/manners should I keep in mind when I visit? Are there any good tourist companies or travel agencies that would be able to work with our short schedule? Are there any agencies or groups that speak both Japanese, English, and Vietnamese?

Also, is speaking Vietnamese fine in Japan? What I mean by that is that both my parents are heavy Vietnamese speakers. They both speak pretty good English, but have trouble with more uncommon words, which worries me when we are going to a country with a language that we do not know. I only know a few words of Japanese here and there from watching a lot of anime. Also, would it be worth it to visit Akihabara, for myself to indulge in the otaku things there?

if you want to travel throughout Japan, order a shinkansen ticket. It is called JR pass www.jrpass.com/?gcli...NsMYaAtkq8P8HAQ

It will help out to travel cheaper... if you are going to specific locations.... well.. Osaka is quite famous city to visit, from there you get to Nara and some other smaller cities. Osaka is super popular for specific foods. Nara for its temples. Okinawa would be cool place to go as well.
In Tokyo... Akihabara - you can go there for sure... you can fins a lot of electrical products there.. and some maid cafes... you would need to move further from the station....
miner8.com/en/13765 - if you are interested in Otaku stuff, check this page out.
Japanese people mostly do not speak English or any other foreign language. I might suggest to find exchange students to help with with showing you the city. Never used agencies there, so... no idea.. i believe you can go local agencies to help you out...