Is this move legal?
Your move is 'IF'
The word YETTS is on the board vertically. I add an I to the left of the S making IS and add F below I to form IF. Is this move legal?Hi - This is a perfectly valid Scrabble play. As long as the letters you play lie in the same row or column and form a valid Scrabble word, it's fine to make other words in the process.
In fact, that's the name of the game, since all the other words you make contribute to your score. In your case, you'll get the score for IF plus the score for IS.
All the best.
P.S. It's pretty cool that you know obscure Scrabble words like YETTS. If you're reading this post and wondering what on earth YETTS means, a YETT is a Scots term for a gate. So it make sense to have more than one of them ;-)