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Old Hindi or Khariboli was the earliest stage of the Hindustani language, and so the ancestor of today's Hindi and Urdu. It developed from Shauraseni Prakrit and was spoken by the peoples of the region around Delhi, in roughly the 10th–13th centuries before the Delhi Sultanate.
During the Muslim rule in India, Old Hindi began acquiring loanwords from the Persian language, which led to the development of Hindustani. It is attested in only a handful of works of literature, including some works by the Indo-Persian Muslim poet Amir Khusrau, verses by the poet Namdev, and some verses by the Sufi Muslim Baba Farid in the Adi Granth. The works of Kabir also may be included, as he use a Khariboli-like dialect. Old Hindi was originally written in the Nagari script (ancestor to the standardized Devanagari) and later in the Perso-Arabic script as well, in Nastaliq calligraphy.
Some scholars include Apabhraṃśa poetry as early as 769 AD (Dohakosh by Siddha Sarahapad) within Old Hindi, but this is not generally accepted.
Alok Rai (2001), Hindi nationalism, Orient Blackswan, 2001, ISBN978-81-250-1979-4, ... on one account, Khari Boli was contrasted with the mellifluousness and soft fluency of Braj Bhasha: khari was understood to refer to the rustic and stiff uncouthness of Khari Boli. The protagonists of Khari Boli returned the compliment: Braj Bhasha was called pari boli – ie supine! ...
Mody, Sujata Sudhakar (2008). Literature, Language, and Nation Formation: The Story of a Modern Hindi Journal 1900-1920. University of California, Berkeley. p. 7.
First Encyclopaedia of Islam: 1913-1936. Brill Academic Publishers. 1993. p. 1024. ISBN9789004097964. Whilst the Muhammadan rulers of India spoke Persian, which enjoyed the prestige of being their court language, the common language of the country continued to be Hindi, derived through Prakrit from Sanskrit. On this dialect of the common people was grafted the Persian language, which brought a new language, Urdu, into existence. Sir George Grierson, in the Linguistic Survey of India, assigns no distinct place to Urdu, but treats it as an offshoot of Western Hindi.
Matthews, David John; Shackle, C.; Husain, Shahanara (1985). Urdu literature. Urdu Markaz; Third World Foundation for Social and Economic Studies. ISBN978-0-907962-30-4. But with the establishment of Muslim rule in Delhi, it was the Old Hindi of this area which came to form the major partner with Persian. This variety of Hindi is called Khari Boli, 'the upright speech'.
Masica, Colin P. (1993). The Indo-Aryan Languages. Cambridge University Press. p. 54. ISBN9780521299442.
Islamia, Jamia Millia (2017). "Employment News". 769:Siddha Sarahpad composes Dohakosh, considered the first Hindi poet
^ Delacy, Richard; Ahmed, Shahara (2005). Hindi, Urdu & Bengali. Lonely Planet. p. 11-12. Hindi and Urdu are generally considered to be one spoken language with two different literary traditions. That means that Hindi and Urdu speakers who shop in the same markets (and watch the same Bollywood films) have no problems understanding each other -- they'd both say yeh kitne kaa hay for 'How much is it?' -- but the written form for Hindi will be यह कितने का है? and the Urdu one will be یہ کتنے کا ہے؟ Hindi is written from left to right in the Devanagari script, and is the official language of India, along with English. Urdu, on the other hand, is written from right to left in the Nastaliq script (a modified form of the Arabic script) and is the national language of Pakistan. It's also one of the official languages of the Indian states of Bihar and Jammu & Kashmir. Considered as one, these tongues constitute the second most spoken language in the world, sometimes called Hindustani. In their daily lives, Hindi and Urdu speakers communicate in their 'different' languages without major problems. ... Both Hindi and Urdu developed from Classical Sanskrit, which appeared in the Indus Valley (modern Pakistan and northwest India) at about the start of the Common Era. The first old Hindi (or Apabhransha) poetry was written in the year 769 AD, and by the European Middle Ages it became known as 'Hindvi'. Muslim Turks invaded the Punjab in 1027 and took control of Delhi in 1193. They paved the way for the Islamic Mughal Empire, which ruled northern India from the 16th century until it was defeated by the British Raj in the mid-19th century. It was at this time that the language of this book began to take form, a mixture of Hindvi grammar with Arabic, Persian and Turkish vocabulary. The Muslim speakers of Hindvi began to write in the Arabic script, creating Urdu, while the Hindu population incorporated the new words but continued to write in Devanagari script.
Shapiro, Michael C. (2007), "Hindi", in Cardona, George; Jain, Dhanesh (eds.), The Indo-Aryan Languages, Routledge, pp. 276–314, ISBN978-0-700-71130-7. Pp. 279–280: "Both within the Hindi and Urdu literary traditions many scholars attempt to assign as early a date as possible for the inception of Hindi, Urdu, or a common Hindi-Urdu literature. R.A. Dwivedi (1966:5), for instance, sees the earliest period of Hindi literature as extending from 760 AD and extending up to the eleventh century. Such an early date for the inception of a Hindi literature, one made possible only by subsuming the large body of Apabhraṁśa literature into Hindi, has not, however, been generally accepted by scholars The more generally agreed upon starting places for 'Hindi' literatures several centuries later (twelfth-fourteenth centuries), lie in several bodies of texts."
Further reading
Strnad, Jaroslav (2013). Morphology and Syntax of Old Hindī: Edition and Analysis of One Hundred Kabīr vānī Poems from Rājasthān. Brill. ISBN9789004254893.