Hi @ Susan Black,
Couple of things to try, to isolate what the problem may be.
Try using the phone in safe mode to see if the voice to text feature is any better.
If the problems don’t occur (or are a lot less) when in safe mode then a downloaded app may be the cause of the problem. The trick is to find out which one. You’ll need to uninstall each downloaded app, one by one and test the phone in normal mode between each uninstall to see if it works OK. When it does then the last app uninstalled is the culprit.
If the problem still occurs in safe mode, try using the earphones with the microphone attachment to check if the voice to text feature works any better. You could also try using the phone in “loudspeaker” (or hands free) mode as well as this uses a different microphone to the one normally used for hand held operation.
If it doesn’t occur when using the above alternative voice input methods then there is a hardware problem with the phone’s internal microphone. Is the microphone inlet hole, located on the bottom edge of the phone, being obstructed at all by a case or cover?