It will start with an Ain. If you pronounce the name, it is like eeeii-shaa-aan whether written ishan or eshan in english. There is a deep EEE sound, which is written in Ain in urdu.
Unfortunately, it's not that simple Aisha... on the outset, the deep eee sound can also be written with an alif (kasra) and a yey together... but that's beside the main point, which is that the combination of a couple of letters can itself act as a root of a word and can be used in deriving meanings.
For example, if ain and sheen are used together, then it forms the Arabic root of 'ish... which stands for "life". That's the problem with new contrived names - you will probably need the help of both a sanskrit and an arabic linguist to determine the best possible combination of letters.