Vowel Movements

You are given a grid of 16 words that need to be grouped together into four categories before the timer expires. To make things slightly more tricky all of the words have had their vowels replaced by other vowels making them surprisingly difficult to read. If you're stuck on a particular word you can trade some of your time to unscramble the vowels. There is also a time penalty for any set of words that is incorrectly grouped, so random guessing and blind clicking are probably not the way to go.