Hi, sorry to hear you're having trouble.
When there are intermittent errors with language prediction quality, it usually means something untoward is going on in the 'swiftkey' folder on your SD card. The method that usually resolves this stuff is doing a clean install, whereby you uninstall SK, delete the folder on your SD card, then reinstall, using Wi-Fi to carefully download the full language modules without the connection dropping.
Give this a shot. If it doesn't help, fire us off a bug report via the option in SK's settings menu on your phone.