Yes, yell is a Scrabble word!
...and is worth 7 points in Scrabble, and 8 points in Words with Friends
yell
Verb
1. Utter a sudden loud cry
2. Utter or declare in a very loud voice
Noun
1. A loud utterance; often in protest or opposition
2. A loud utterance of emotion (especially when inarticulate)
What Scrabble words can I make with the letters in yell?
3 Letter Words
2 Letter Words