I've had my DX for 3-4 weeks. I made some calls midday today and the phone sat in my bag for the rest of the afternoon. I pulled it out this evening to make some calls, and suddenly, I have NO sound from the speakers that are call-related: no ring tone, no sounds from the other end, either a person/voice mail answering. I *do* have keypad sounds when dialing.
This is very odd.
I've looked at all my settings. I don't think I hit something by accident to silence the speaker. I still get other sounds out of the speakers, such as music or notification sounds.
I don't use bluetooth. Even when I plugged in my Apple iPhone earbuds with the inline mic I don't get any sounds after dialing.