The Letter Q:
Scrabble players are acutely aware that Q is a tricky letter. To use a Q in the game, a player must also find an available U. The fact that Q is the second most rarely used letter in the alphabet certainly doesn’t make using Q any easier.
Let’s quest towards resolving the questions of quarrelsome Q, the 17th letter in the alphabet.
In English QU is always used as a digraph (a pair of letters representing a single speech sound) for the sound /kw/ (a voiceless labiovelar stop). Q’s pairing with U is a Latin invention that has its origin in Greek. The letter Koppa, which Q is based on, would appear before a rounded vowel where otherwise a sound like /k/ or /g/ would be used. But a few other letters, like C, also designated the same sound but in different letter combinations. As C gradually came to represent more and more of these instances, Q became primarily dependent on U to express any sound at all. This is quite a quibble for a full-fledged member of the Latin (now English) alphabet.