Go into Free Play > Language > Word Wheel and in an internet browser (phone, tablet or PC) and do the following:
Simply use a scrabble solver, such as http://www.anagrammer.com/scrabble/
to enter the letters as the come up on screen, and then decipher the word by unlocking the solution via the site. The words are never overcomplicated, and simple enough for children to generally know - Or at least is my understanding.
Don't worry if your not quick at entering / have to scroll around the wheel - just ensure you make no mistakes in inputting letters into the website and into the game, and it will work (For reference, my time was 1:49.36 to achieve this trophy).