Firstly, the armies of Babur and even Humayun were vastly different, and by the time of Akbar, with the Mansabdari system reforms (they always existed, but Akbar tied it to a sort of a vassal levy type system-for lack of a better expression), the structure, composition and indeed the ethnic make up of the armies changed again. The next major change was made by Aurgangazeb who did away with the small standing army + backed up by levies of the "Mansabdars" structure to a humongous standing army to suit the almost never ending wars he had to fight in the Deccan. So there was never one specific Mughal army structure, but multiple iterations and reforms made it a very fluid organisation.

During Babur and Humayun's time, yes, the armies and the generals came from Turkish / Persian stock, though the Baburnama is largely silent on the ethnic mix of his army.

The armies of Babur and Humayun (and to a smaller extent, later Mughal armies) had the following structure at the core,

• The Yikitlar - The core group of leaders and bodyguards, these were not just of the same ethnic grouping, but came from the same clan / village (think of Saddam's Tikriti clansmen)

• The larger group (the mass of the army if you will) came from the Beglar (allies or chieftain allies). Now, till Humayun's time, the Beglar were mostly Timurid origin and their soldiers also reflected this ethnic grouping.

• Ichkilar (individual) and Mehman (guest) Beglar (guest chietains or mercenary companies) - One could use the term 'Mercenaries' to define them. These were independents, minus caste, creed or religion (Akbar and after Mughal armies even had European adventurers fighting for them as Ichkilar). The backbone of the pre Akbar Mughal cavalry were the Qazzaqi's (Steppe horsemen), but post Akbar, the Qazzaqi's moved to the Yikitlar grouping while Rajput cavalry became the backbone of the Mughal cavalry.

The Baburnama does state that post his consolidation of his conquests, Babur started to recruit "Hinds" (Hindus?) to his ranks, but considering the fact that he had defeated the Lodi's whose soldiers were of Muslim stock (of varied ethnicity) whose soldiers also flocked to Babur's banners, the catchall phrase might just be an error.

Both Babur and Humayun though did not really drive any military reforms, that was initiated by Humayun's mortal enemy - Sher Shah Suri (who himself modeled his reforms on Ala Ud Din Khilji). Interestingly, Sher Shah Suri recruited mostly from Pashtun (and other Afghan, the only Indian emperor who is known to have imposed the draft) stock initially, but later created a sort of a loose meritocracy which enabled Hindu's like Raja Hemu to rise from possibly being an independent mercenary to the leading general commanding his armies (though under Sher Shah's son, Islam Shah)

Now, post Akbar, when the Hindu nobility (esp the Rajput clans) rallied to Akbar, the Beglar comprised of multiple Indian ethnicities, while the Yikitlar remained Persian / Turkish.

Ala u Din Khilji's reforms pushing for a large centralised army were complemented by Sher Shah Suri's push for the same, but after quelling the multiple rebellions, Akbar's empire did not have the same need for a large standing body of troops, hence he reformed the Mansabdari system to reduce the burden the military placed on the exchequeur. Under this, and pertinent to the question at hand, each Mansabdar (think of them as a vassal serving their liege lord) had to when asked, provide an x number of troops (related to their rank in the court). This is when the Mughal army truly became...cosmopolitan and comprised of multiple ethnicity's. As the empire expanded and stabilised, Akbar created the rank of the "Sabhdar's" (provincial Generals) who each could appoint their own mansabhdars. This expanded the ethnic reach of the army substantially. With the expanding borders, came into the Imperial Army fold, new ethnic stock such as the UP (modern day) musketeers who were famed for their musketry even upto the British army period. As his empire expanded south, came the warlike tribes of modern day Karnataka and AP (loosely termed the "Telegas" by the Mughal administration). As his empire expanded to the West came the Habshis (African origin peoples, mostly from Ethiopia)

Given that the Mughal Mansabdari corps had ethnic stock from all over - Iran, Rajput, Marathas, Middle East, who then had feudatory obligations to provide a certain number of men based on their rank, the Akbar era Mughal army must have been almost as cosmopolitan as say the Austro Hungarian army during WW1.

One interesting...group would be the Sayyids, who were recruited into the Shamserbaz (shock troops?) - these were essentially warrior Sufi monks who trained in the martial arts and were supposedly extremely effective.

These changes remained, even till the time of Aurangazeb, but with the Hindu, Sikh and Deccani Mansabdars getting into revolt, along with revolt on the Eastern borders, the army must have been at its homogenous maximum since Babur.

In a nutshell, starting midway into Humayun and till Alamgir, the Mughal army would have had Mongols, Turks, Afghans, Iranians, Arabs, Rajputs, Eastern Indians, Telegas, Africans, Europeans, Bhils, North Eastern mercenaries (the Mughal empire never did reach till the NE, so you didn't have NEastern Mansabdars) amongst others....must have made for one colourful and impressive sight.

The reforms also changed the officer composition (can expand on it if you wish, but the Mughal officer hierarchy under Akbar is a huge topic of its own)

My sources are mostly,

• Baburnama,

• Akbarnama & Ain I Akbari

• Mughal Warfare: Indian Frontiers and Highroads to Empire, 1500-1700 by Jos Gommans,

• Warfare and Weaponry in South Asia 1000-1800 (Oxford in India Readings: Themes in Indian History) by Jos Gommans and Dirk Koloff