I guess some context is in order. So, suppose two people were talking about smartphones and suddenly one of them wants to talk about something somewhat related, like a camera or a handheld. Luckily this happened in Japan. Is it ok (or grammatically correct) not to say “speaking of such…” in this case?

At our very least: I don’t have any doubt about the reasons why I don’t like to be mentioned in your everyday life. Thank you!