Hello there, Without the information requested in my first/previous response, I can only give you a general answer, but I hope this helps.
First, you can reset your Samsung keyboard and see if it helps. On your Tab, open Settings > Applications or Apps, then select All at the top. Now, find and select Samsung Keyboard, select it, tap Store, and tap Clear Data
This will reset the keyboard. Remember, if you have shortcuts saved on this keyboard, this will reset it as well.
Then check if it is working.
Please let me know if that didn't work, so I will continue to help you until we fix the problem
Note: This is not my final answer. I strive to provide Excellent service or 5-star service. If you feel you've received anything less or if you are not satisfied or if my solutions didn't work, please don't rate the answer bad or poor or anything and instead let me know by replying here and I will stay with you and try my best to help you until you are fully satisfied or the issue is resolved.