This document discusses the phonetic mechanism of qalqala in Arabic pronunciation. It begins by explaining that voweled letters involve parting the articulation and mouth movement, while plain letters involve collision of articulation without mouth movement. Qalqala letters violate this rule for plain letters - when bearing a sukoon, they involve parting the articulation but no mouth movement. This causes annoyance that is resolved by the qalqala pronunciation. The document defines qalqala, lists the letters involved, and discusses differences in articulation and states of the letters. It also divides qalqala into lesser and greater types based on word position. In total, the document provides technical details about the unique phonetic