I learned the word from my mother and she would pronounce it - Eye yah. I believe that it comes from Hindi, which is an oral language only. Because of the lack of being pegged to the written word, it tends to evolve in any direction that it is needed. It is the Pigeon English of the Indian sub-continent.
Not true at all. Hindi as a written language goes back hundreds of years, in Devanagari script in India and in Muslim areas including Pakistan in Arabic script. Other main languages like Bengali or Tamil also have very long written records. But it may be true of more local languages that they were originally oral only.
My Mum was born in India and had an Ayah.
Same here. My grandfather was a Consulting Engineer and probably most of the Indian engineers he worked with were trained in English so he didn't have to learn too much of the local language(s).
I asked mum once, did she ever learn any Tamil? She said no, but she did learn some Hindi due to spending all day with the ayah.
Once the family was out in the car and got lost between villages. Father asked someone for directions but he wasn't sure he understood the reply. My mum who must have been no more than six, took control and said No Daddy he said go along here and turn right and ...