Scrabble of points for each lettered tile is based on the letter's frequency in standard English; commonly used letters such as vowels are worth one point, while less common letters score higher, with Q and Z each worth 10 points. The game also has two blank tiles that are unmarked and carry no point value. The blank tiles can be used as substitutes for any letter; once laid on the board, however, the choice is fixed. Other language sets use different letter set distributions with different point values. Tiles are usually made of wood or plastic and are square and thick,
Tile tracking or 'consonant-heavy', how many S's or blanks are unseen, if an opponent is likely to have a bingo on their rack, or which tiles to play or conserve. For example, if Alice has the option of playing J(I)NN or J(I)LL, and four N's and zero L's remain unseen, then assuming both plays are otherwise equal (in terms of score, openings for the opponent), J(I)NN is likely the better play. Letter frequency lists for both Scrabble and Words with Friends are easily accessible (some versions of Scrabble have the tile distribution directly on the board) and, unlike word lists, using them