मानक साहित्यिक भाषा
The speech variety based on the dialects spoken in and around Darbhanga-Samastipur has come to be regarded as the standard literary medium, although the variety based on Saharsa dialect has also been used by certain writers. The standardization had been accomplished quite some time back, particularly after 1940s. But the question of whether one should have unitary literary standard is still an open question.
Of course, in his Linguistic Survey of India, Grierson (1908: 13-4; Vol. V. ii) states that “Maithili is spoken in its greatest purity (Standard Maithili) by the Brahmanas of the north of the Darbhanga and Bhagalpur districts and those of Western Purnea. It is also spoken with some purity, but with more signs of wearing away of infections in the south of Darbhanga district, and in those portions of the then Monghyr and Bhagalpur districts which lie on the northern bank of the Ganges. This may be called Southern Standard Maithili. He then goes on to mention its other varieties: Chhikaa-Chhikii born out of contact between Maithili and Magahi in the south, Western Maithili (which has a lot of Bhojpuri element in it), and the Jolahaa bolii (also known as the Shekhai or Musalmani, and has traits of Awadhi)- which is basically a cover term used for Muslim speech variety in Mithila. It must be borne in mind here that by the name “Standard”, Grierson was referring to mainly accepted spoken standards.
Today, there are multiple literary standards available and used concurrently depending upon the origin of the given author.