I would like to know some things about the Indian Army (1903-1947), namely:
How was language handled, considering that India has a great number of languages and (as far as I'm aware) a large number of officers were actually white British or born in India to white British parents?
What was the position of white British officers in the army? Were they a majority in the officer class? How were they received by the native soldiers? Were they considered in any way different to those of equal rank in the British Army?
The language was handled just as it is handled now. The officers sometimes learnt the local language, but mostly, they gave their orders in English and their assistants or local officers executed them. All native Indian officers knew English, and passed on the orders in the local language.
Indian soldiers were remarkably loyal to the empire. I say "remarkably" because a casual observer might believe that the natives had no interest in the well being of the empire. A British officer did not have to worry about the native officer/sepoy messing up his order due to malice.
Many scholars, like R.C. Majumdar (Three Phases of India's Struggle for Freedom) argue that it was the sympathy of the average Indian soldier towards the INA and its beliefs that sealed the freedom of India.