Are one-letter words playable in Scrabble?

No

Single letters are not allowed to be played in Scrabble. Although many standard dictionaries class single letters as words by themselves, the Scrabble dictionaries do not recognize them as valid. Because of this, it is not possible to play them in a game.

Although a single letter by itself cannot be played. It is possible to place just a singular letter tile in a turn. However, this letter tile must extend off of an existing word on the board to make a new word of two characters or more.

For example, if I played the word “cat”, my opponent could place the letter “s” to create the word “cats.” This would be a completely valid move using just a single letter tile as it creates a valid 4-letter word.

Checking a words validity

If you wish to check a word is valid to be played in Scrabble (regardless of the length) dictionary checkers are great online tools to do so.