The speakers are distributed unevenly, as shown in the map.[2]The proto-languages of the eastern Magadhan languages. Kamarupa Prakrit corresponds to ?proto-Kamarupa here, a hitherto un-reconstructed proto-language. The period corresponds to earlier than 1250 CE, when proto-Kamta began to innovate unique features.[3]
KRDS lects (or Kamta, Rajbanshi, Deshi and Surjapuri lects) are a cluster of modern lects that are phylogenetic descendants of the proto-Kamta language.[4] The proto-Kamta language began differentiating after 1250 around Kamatapur, the capital city of Kamata kingdom, as the western branch of the proto-Kamarupa,[5] whereas the eastern branch developed into proto-Assamese. Since the 16th century the proto-Kamta community has fragmented giving rise to the differentiated modern lects.[6] The modern lects are:[7][8] Kamta (Assam and West Bengal), Rangpuri (Bangladesh), Rajbanshi (Nepal) and Surjapuri (Bihar).[9]
These modern lects could be categorised into three groups: western, central and eastern.[10] Unlike the Assamese, Bengali, Hindi and Nepali languages which were standardised and propagated in the 19th and 20th centuries,[11] the KRDS lects were not standardised. As a result, the KRDS lects became diglossic vernaculars to these standard varieties and acquired phonological and morphological features from them.[12]
Nevertheless, two standards are emerging within the KRDS lects: a central Jhapa variety targeting speakers in Nepal, and an eastern Cooch Behar variety targeting speakers in northern West Bengal and western Assam.[13]
Proto-Kamta
The development of proto-Kamta (also called proto-Kamata) was the result of Sandhya, a ruler of Kamarupa Nagara (North Guwahati), Kamrup moving his capital[5] to Kamatapur and establishing the Kamata kingdom, thus carrying the native language along with.
^"Proto Kamta took its inheritance from ?pKamrupa (and before that from ?pGaudaKamrupa), innovated the unique features outlined above during AD 1250–1550, and then split into three main sections (western, central, eastern)..." (Toulmin 2009:221)
^"The linguistic history reconstructed here shows that all KRDS lects—whether the ‘Rajbanshi’ of Morang district in Nepal, the ‘sthaniyo bhasha’ (local language) of Rangpur in Bangladesh, or the ‘Kamta’ of Cooch Behar in India—share a common ancestor, which for historical reasons may be termed proto-Kamta." (Toulmin 2009:246)
^ ab"On sociohistorical grounds, this stage is termed ‘proto Kamta’ ... and assigned the chronology of approximately AD 1250–1550: sandwiched between the establishment of the Kamrupa capital at Kamtapur in 1250, and the political (and plausibly linguistic) expansion under Koch King Nara Narayana in 1550." (Toulmin 2009:13)
^"Furthermore, since the 16th century, the KRDS lects have undergone differentiation from one another. This diversification is not merely the result of ‘contamination’ with other languages; it is natural in human society that lects spoken by differentiated speech communities tend to become linguistically differentiated." (Toulmin 2009:247)
^"The categorisation of KRDS lects as western, central and eastern (which is verified in the present study) was first put forward by Barma (1991)." (Toulmin 2009:11)
^"The standardisation of Bangla, Asamiya, Nepali and Hindi, and the propagation of these standardised varieties during the 19th and 20th centuries has had significant effects upon the KRDS lects." (Toulmin 2009:247)
^"During the modern KRDS period various phonological and morphological features have entered KRDS lects due to increased diglossia with standardised State languages." (Toulmin 2009:13)
^"[T]here are today two distinct standards emerging in the literature of KRDS speakers. The variety of central Jhapa features in an increasing number of publications aimed at speakers in Nepal. The variety of eastern Cooch Behar is likewise increasingly used for publications aimed at the Rajbanshis and deshi Muslims of northern West Bengal and western Assam. (Toulmin 2009:247)
