The Mudita Group is singing during a saturday evening satsang the kirtan Kali Kali Maha Kali Kali Durge Ma, which can not be found in the Yoga Vidya Kirtan Songbook.
Kali's earliest appearance is that of a destroyer of evil forces. Over time, she has been worshipped by devotional movements and Tantric sects variously as the Divine Mother, Mother of the Universe, Adi Shakti.
Kali is often portrayed standing or dancing on her consort, the Hindu god Shiva, who lies calm and prostrate beneath her. Kali is worshipped by Hindus throughout India.
There are many english seminars every year in the different ashrams of Yoga Vidya. You can find them all by clicking here: yoga-vidya.org/english/seminar/.