I don't know about Hong Kong, other than that it is a former British colony, so you are likely to find English speakers around.

As for Japan, all major signs in airports, train and subway stations, etc., are in English and Japanese, and increasingly in Korean and Chinese as well. The affordable restaurants are likely to have either picture menus or plastic models of the foods in the window.

Everyone under the age of about 70 has had at least a bit of English in school, although they may not remember it. Speak slowly, and if that doesn't work, write down your question in block letters. Naturally, younger people remember more English than older people, and you may be lucky enough to run into someone who has lived overseas and speaks very good English.

In addition, there are a lot of expatriates in the major cities of Japan. I don't currently live in Japan, but on nearly every trip, I've had tourists stop and ask me questions, most of which I can answer.

If you ask the price of something, store clerks are likely to show it to you on a calculator.