I have the same problem and it seems to happen only when my battery is at less than 20% and when I've inputed more than four lines.
Any actual answers besides using another text app???
I'm having this same issue, upside down question marks between each letter of my text. It's happened twice this week both to different iphone users. My battery is fully charged, they were both longer texts. There were no emoticons or Spanish characters used. Is there a solution or explanation to this?
My texts frequently send upside down question marks and other random marks. Everyone I text is a Verizon customer, no one is using the iphone and this never happened on my Droid. The Droid X randomly sends my texts with characters and later texts are sent properly.
I don't use smiley faces only actual text. It is random and it is driving me crazy. I am seriously considering going back to my original Droid.
I figured out this problem of why upside down question marks appear in text. If you hold down the question mark symbol for 2 seconds then release and press the question mark symbol again regularly, you will have an upside and right side up question mark