Neither text suggestion nor Word Flow is working on my Nokia Lumia 920. I just got my phone updated with Lumia Cyan.
How can I get those features to work?
Word Flow and text suggestions aren't available with all languages. To see if your current language is supported, see Windows Phone feature and service availability.
If your language is in the list, go to Settings → Keyboard, tap on your language and make sure that the "Suggest text" and "Type as I flick through letters" options are enabled.
For more information on using the on-screen keyboard, see Windows Phone typing shortcuts.
Found this on googling.
Just long press your language and change it and retry.
Editing after the comment for proper answer.
In windows keyboard, there is a button, to change your language. Long press the button, 3-4 languages will pop-up depending on number of language keyboards you installed. Change it to your geo-location and try, the keyboard will work. If it is just English, then changing from EN-US to EN-UK will work or vice versa.