Old Hindi

Hindustani (Hindi: हिंदुस्तानी Urdu: ہندوستانی) is one of the predominant languages of South Asia, with federal status in India and Pakistan in its standardized forms of Hindi and Urdu. It is widely spoken and understood as a second language in Nepal, Bangladesh, Sri Lanka and the Persian Gulf and as such is considered a lingua franca in the Indian subcontinent. It developed in North India, principally during the Mughal Empire, when the Persian language exerted a strong influence on the Western Hindi languages of central India. This led to the creation of Rekhta, or "mixed" speech, which came to be known as Hindustani, Hindi, Hindavi, and Urdu. This form was elevated to the status of a literary language, and after the partition of British India and independence this collection of dialects became the basis for modern standard Hindi and Urdu. Although these official languages are distinct registers with regards to their formal aspects, such as modern technical vocabulary, they continue to be all but indistinguishable in their vernacular forms.

Most of the grammar and basic vocabulary of Hindustani descends directly from the medieval language of central India, known as Sauraseni. After the tenth century, several Sauraseni dialects were elevated to literary languages, or khari boli ("standing dialects"), including Braj Bhasha, Awadhi and the language of Delhi (the latter still goes by the name Khari Boli in the rural areas outside the city of Delhi itself). During the reigns of the Turko-Afghan Delhi Sultanate and the Mughal Empire, where Persian was adopted as the official language and Delhi was established as the capital, the imperial court and concomitant immigration infused the Delhi dialect with large numbers of Persian, Arabic, and Chagatai words from the court; the introduced words were primarily nouns and were employed for cultural, legal and political concepts. The new court language developed simultaneously in Delhi and Lucknow, the latter of which is in an Awadhi-speaking area; and thus, modern Hindustani has a noticeable Awadhi influence even though it is primarily based on Khari Boli.

...
Wikipedia