In email, every letter "y" is capitalized when it is incoming.
BB will let me type a normal sentence in an outgoing email. But when it comes back, both the reply and my initial email have every letter y capitalized.
Sample Outgoing:
"Dear Friend, Hey, you down for drinks today?"
When the reply comes in to me:
"I don't want to because You're going to be crankY about Your blackberrY."
>>"Dear Friend, HeY, You down for drinks todaY?"
Sounds like the Y key may have something stuck in it that makes it pause just long enough to register as a capital letter. I had this happen with the 'T' key once. a piece of gunk had worked its way into the keyboard and a cleaning brought function back to normal.