Punjabi developed from the ancient language of Prakrit developed simultaneously with Sanskrit. Punjabi is known to have been spoken by the Indus Valley civilization according to DR Jaspal Singh Mayell. "Possibly, Punjabi is the only major South Asian language that has this kind of tonal character. There does seem to have been some speculation among scholars about the possible origin of Punjabi's tone-language character but without any final and convincing answer..."