Q is the least (or second least, depending on method of counting) frequently used letter in the English language. It usually occurs as the sequence “qu”, pronounced “kw” at the beginning of syllables, as in “question”, or as the sequence “que” at the end of words, pronounced “k”, as in “clique”.
Its relative rarity in English orthography means that in the word game of Scrabble, Q scores the maximum 10 points (like Z, the other least frequent letter in English), compared with the frequent, thus one-point, vowels and L, N, S, T, R.