If you spoke Japanese, maybe the salesperson would likely be able to communicate more. Could be that salesperson didn't feel confident with their English? Who knows, maybe you got a salesperson who speaks perfect English but just not talkative (your post didn't state anything about the salesperson's English capacity nor your capacity for Japanese - and I don't want to make an assumption). The larger stores will generally have an English speaking sales associate on the payroll. And if you can, try to make an appointment through your hotel concierge. It's a pain to have to announce yourself before you come, but it is part of the Japanese culture, and it does usually mean you get an improved experience as they will try to find an English speaker for you or at least print out specifications in English for you. I generally have the concierge call in advance on my behalf and I even ask if I need to prepare to take off my shoes.