Rev. Sidney Endle was the first scholar and writer who brought Bodo language into regulated and written form in the last part of the nineteenth century through his scholarly books, 'An Out Line Grammar of the Kachari (Bârâ) Language as spoken in district Darrang, Assam with illustrative sentence, Notes, Reading lessons, and a Short Vocabulary' - Shillong, 1884 in Roman script.
  
The European missionaries first introduced Bodo language in their missionary schools situated in the Bodo inhabited areas along with translation of Bibles from English into Bodo. Reading and learning in Bodo by Bodo children continued up to the early part of the twentieth century through Roman script, but that practice was stopped when the wave of Swaraj Movement took a serious turn to hate over the European missionaries who propagated Christianity amidst the illiterate Indians and Bodos who were then best influenced by the Hindus through Guru Deva Kalicharan Brahma of Kajigaon in Goalpara district of Assam, who became Sib Narayan Parama Hongso of Calcutta who profounded a refined Hindu religion called Brahma Dharma ( Brahma religion) and that time. It was happened so, as because of fact that the Bodo guardians who were so afraid of being converted into Christianity by those Christian missionaries who were in-charge of teaching Bodo in Roman Script in their missionary schools, stopped sending of their children to such missionary schools (1916).

  
Indeed large scale conversion into the Christianity amidst the Bodo people was checked by that Bodo disciple of Bengali refined Hindu religion propagator Siva Narayana Parama Hongso as he was a man, possessing of strong personalities; successfully spread this Brahma Dharma amongst the Bodo Kachari people and later he was known as the Guru Deva Kalicharana by the Bodos.
  
A religious book of that Brahma Dharma called Khriya-Dorpon, meaning a rule of performing rituals was published in Bengali language and later it was translated into Bodo language by Sri Kalicharan Brahma of Simbargaon, a disciple of late Guru Deva Kalicharana and who wrote an autobiography too of his Guru Deva.
  
Guru Deva's one of the so many best contributions to the Bodo society was a book written in Bengali Assamese script known as Boroni Jolonga, meaning -'a book of Bodos concerning to medicine' by which the literate Bodos could manage certain medicines themselves while their family members happen to suffer from fever.
  
Although the Brahma Dharma was spread over the Bodo people even then the traditional origin Bathou (Siva worship) Mongolian religion continued to exist.
Guru Deva Kalicharana launched a vigorous movement amidst the Bodo society to eradicate wine, and taming (rearing) of pigs and poultry, - the systems of which were prevalent in their society since the time immemorial and thereby adversely affected in the economy of the common Bodo people by the latter two. He had been compelled to hire this Brahma Dharma from Calcutta so as to remove the 'bar of entrance' is untouched ability on the part of Hindus over the Bathou Mongolian religionists to their homes and hotels etc., which was so greatly prevalent in the Hindu society in the pre-independence era.
  
Guru Deva's greatest contribution was the reformation that he brought among the Bodo society. He organized Bodo Samaj (Bodo Society) and prepared a code of conduct of the Bodo Society in line of Hindus keeping the basic structure of Bodo Mongolian origin of 5 (five) Asharas, a code of punishment and trial viz, - Ogorbad, Daokibad, Fongslotbad, Gandubad, and Kaoalibad along with adjustment to the penal code of India (P.C.I & C.R.P.C.I), which is still followed by the Bodo Samaj and known as Bodo Pandu Lipi. Sub Division or Anchalik wise Bodo Samaj are still in function in every Bodo inhabited areas and villages.
  
In the field of social system of marriage there were several systems viz, - escaping away the girl by the boy (Dânkharlangnai), dragging the girl away by force (Bânai), body offering i.e. the girl herself goes at the house of the boy whom she loves (Kharannai), looking for girl by guardian (Nainanâi lainai), widowed marriage (Dongkha Habnai), adaptation-son-in-law's marriage (Gârjia janai) and out of which most marriages occure now a days only from the 'body offering' and 'looking for girl by the guardian' systems.
  
Guru Deva reformed the Bodo society marriage system and eradicated the first two systems as stated above which were considered to be inhuman and barbarous in nature.
  
Thus performance of martial ritual in form a 'Jaygya' fire ritual as prevalent amongst the Brahmins was being introduced along with the rule of completion of Saptapadi (seven circles) after spread of the Brahma religion among the Bodos. However, the primitive form of the martial ritual in the form of 'Hathasuni' continue to exist. No Caste bar there among the Bodo marriage as prevelant amongst the Hindu like Anuloma and Protiloma marriages as guided by the Mitakshara and Doyabhaga Hindu thoughts of the Hindu Family Laws.
Although such social changes were brought into the Bodo society yet the practices of taking wine and pork (non-Hindu character) continues as a whole amongst the Bodo and Mongolian characters are thus maintained still.
Guru Deva Kalicharana encouraged the educated Bodos to practice Bodo language in the form of literary language and he himself wrote a book in Bodo "Boroni Jolonga".
  
He established a 'Brahma Boarding' at Dhubri were the Bodos could take shelter while going to offices and court at Dhubri, the headquarter town of the Goalpara district. Many Bodo students stayed there as the lodging and used to received to their educations. Those Bodo students studying at Dhubri town first brought a Bodo Magazine 'Bibar' by name which was contemporary to 'Bahi' of late Rose-Ras Lakshminath Bez Barua the founder of modern Assamese literature.