Hindustani and a member of the Western Hindi category of Indo-Aryan languages, 75% of Urdu words have their etymological roots in Sanskrit and Prakrit, and approximately 99% of Urdu verbs have their roots in Sanskrit and Prakrit. 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 Delhi dialect. In these cities, the language continued to be called "Hindi" as well as "Urdu". While Urdu retained the grammar and core vocabulary of the local Hindi dialect, it adopted the Nastaleeq writing system from Persian. The term Hindustani is derived from Hindustan, the Persian-origin name for the northwestern Indian subcontinent. The works of the 13th century scholar Amir Khusro are typical of the Hindustani language of the time: सेज वो सूनी देख के रोवुँ मैं दिन रैन । पिया पिया मैं करत हूँ पहरों, पल भर सुख ना चैन ॥ sej vo sūnī dekh ke rovũ ma͠i din rain, piyā piyā ma͠i karat hū̃ pahrõ, pal bhar sukh nā cain. Seeing the empty bed I cry day and night Calling for my beloved all day, not a moment of happiness or peace. The language went by several names over the years: Hindavi ("of Hindus or Indians"), Dahlavi ("of Delhi"), Hindustani ("of Hindustan") and Hindi ("Indian"). The Mughal Emperor Shah Jahan built a new walled city in Delhi in 1639 that came to be known as Shahjahanabad. The market close to the royal fort (the Red Fort) was called Urdu Bazar ("Army/camp Market", from the Turkic word ordu, "army"), and it may be from this that the phrase Zaban-e-Urdu ("the language of the army/camp") derives. This was shortened to Urdu around the year 1800. The Mughal term Ordu with the local equivalent Lashkari or "camp language" (cognate with the English word, "horde"), was used to describe the common language of the Mughal army. The language spread from the interaction of Persian-speaking Muslim soldiers to the local people who spoke varieties of Hindi. Soon, the Persian script in the cursive Nasta'liq form was adopted, with additional letters to accommodate the Indian phonetic system. A large number of Persian words were adopted in Hindustani, as were even grammatical elements such as the enclitic ezāfe. The official language of the Ghurids, Delhi Sultanate, the Mughal Empire, and their successor states,