I work with a vendor who speaks Japanese. I told her I was studying Japanese and now she’ll write to me in a mixture of Japanese and English. Yay!
But now what? What are business appropriate phrases? I can こんにちわ and ありがとう ございます. When she says よろしくおねがいします do I say it back? When she sends something in an email and says ありがとう ございます , do I say どういたしまして or ありがとう ございます back?