The Mughals are from a long Turco-Persian tradition, though, which matters more than our modern concept of their 'race'. Persian was interrupted as a lingua franca in the Persian region by Arabic, but a new form of Persian, assisted by co-opting Arabic vocabulary and script, became popular because it was used in centres of culture and power, which were focused around rulers. This spread as the various Turco-Persian empires spread, with Persian often having centre stage as the courtly language, but also becoming endorsed as an 'official' language, and even when it was not, it became more popular for songs, poetry, and literature, and was often the first choice as a lingua franca at the borders of the empire.

Geography. Turkic tribes were converted by the Persian part of the islamic world. In terms of culture and civilization, the Persian world endured in the bosom of the Arab conquests, somewhat comparable to how Rome conquered the Hellenistic world & absorbed its culture. Consider that prior to being absorbed into the islamic world, the Turkic groups lived in tribal (semi)nomadic societies that had little to offer in terms of civilization in light of running an empire. All of this, from higher culture to administrative trappings, the Turkic groups learned from the Persian world. As the Seljuqs burst out from behind the Oxus and into the islamic world, they took that all the way to the gates of Jerusalem & into Anatolia.