SwiftKey has a resilient language model download service, so if you have trouble, make sure you have enough space on your SD card and try redownloading with a strong data connection (such as Wi-Fi).
If the issue continues, please try the following:
1. Go to phone menu, Settings->Applications->Manage Applications->SwiftKey->Clear data.
2. Uninstall the application
3. Download and install it again
Please feel free to contact us directly if your issue persists.