Qalqala is a term used in Arabic language and Tajweed (the rules of Quranic recitation) to describe the bouncing or echoing sound produced when pronouncing certain Arabic letters (consonants) known as the Qalqala letters. These letters are ق، ط، ب، ج، د, and when they appear with sukoon (a diacritic mark indicating the absence of a vowel sound) in the middle or end of a word, they are pronounced with a bouncing sound known as qalqala.