Why Divine Mother Maha Kali Is shown with Her Tongue?

Divine Mother Maha Kali killed the demon raktabija, whose each drop of blood produced another demon. raktabija symbolises chronic desires in human beings; with his drops of blood symbolising incessant desire.

Divine Mother Maha Kali Devoured all the drops of his blood and thereafter Killed the demon raktabija. She Is depicted With Her Tongue symbolising She Can Make Whom She Wills free from chronic incessant desires.