Hey gamer520,
If you haven't already, make sure you're fully updated to the latest version of 161.1 by tapping Settings > General > About. If an update is needed, back up your iPhone first. Updating helps by installing bug fixes and security updates. Here's a guide to follow, just in case: Update your iPhone or iPad - Apple Support
Update your iPhone or iPad wirelessly
1. Back up your device using iCloud or your computer.
2. Plug your device into power and connect to the internet with Wi-Fi.
3. Go to Settings > General, then tap Software Update.
4. If you see more than one software update option available, choose the one that you want to install.

5. Tap Install Now. If you see Download and Install instead, tap it to download the update, enter your passcode, then tap Install Now. If you don't know your passcode, learn what to do.
If you're already updated or the behavior continues, toggle Predictive Text off and back on to see if refreshing the setting helps. To do that tap Settings > General > Keyboard > Predictive off. Wait a few seconds and turn it back on. Here's more information on that feature too: How to use Auto-Correction and predictive text on your iPhone, iPad, or iPod touch - Apple Support
If the issue continues at this point, we recommend reaching out to Apple Support to look into this with you more. They can be reached here: Contact - Official Apple Support
Thanks for participating in Apple Support Communities.
Take care!