what is qalqalah?
Answer
The qalqalah is defined as a disturbance. It is a characteristic found in the letters of the group:
when they have no vowel (are saakin). The letter is then pronounced not completely saakin nor is it pronounced with a vowel, instead it sort of "bounces." You can read more about how the qalqalah is formed in the following link:
http://www.abouttajweed.com/the-qalqalah-as-sakt-and-al-ikhtilaas/the-qalqalah-mechanism.html