Qalqalah is a brief, controlled rebound in the articulation of certain unvowelled consonants. The release must not become a full fathah, kasrah, or dammah appended to the word.
Its five letters are remembered in قُطْبُ جَدٍّ: ق، ط، ب، ج، د.
Practice: pronounce «أَقْ», «أَطْ», «أَبْ», «أَجْ», and «أَدْ» briefly and distinctly, without adding an extra vowel. A qalqalah letter that becomes still at a pause can also be practiced. ت has shiddah but is not one of the qalqalah letters.