This is an emerging issue that seems to be some sort of a bug perhaps in some of the note 4's. I haven't read anything that successfully removed the issue other than a full factory reset and restore, but I would think you may also try force stopping and clearing data on the app through your application manager.
Normally that would work, but I have read several accounts from people having this issue with their calculator, and turning off the accessibiility services has not been successful. It might still work, but this seems to be another issue.
well its an app for sure that is causing that issue. in my case i have liteflow app. and when i use the calculator it talks. so from my experience i shut that off and the calculator does not talk..with the note 3, it actually would talk on the native browser & calculator.