The word Prakrit means means Prototype. Pra (prime, first, pre-) + krt (created). The word Sanskrit means completed, refined, perfected. Sum (Complete) + krt (created). Virtually every Sanskrit student in India learns the traditional story that Sanskrit was created and then refined over many generations (traditionally more than a thousand years) until it was considered complete and perfect. The original crude language from which Sanskrit was derived could be Prakrit.
Some scholars include all modern Indic languages ultimately derived from Sanskrit under the rubric of "Prakrits"; others prefer to designate as Prakrits only dialects and languages that were used in antiquity. Some definitions state the Prakrit period as being between 1200 - 1000 CE, whilst others place the period between the third century BC and the fourth century CE.
Perhaps the most important Prakrit today is Pali, which has survived as the language in which the Theravada Buddhism records the Buddhist scriptures. In this capacity, it has influenced both Sanskrit and modern Southeast Asian languages, such as Khmer and Thai.
One form of Prakrit is Ardhamagadhi.