When we change/mispell ع into another letter such as أ in some words, the meaning can also be changed.
ألى : النعمة
(Favor, Grace, ?)
But, in the daily conversation, people will hear us from the whole context. Understandable or not - it can be 50 : 50? So, we should try to avoid our misspelling.
Thanks a lot — five months ago! I actually thought of the difference between عَلا and عَلى. I am vere concerned about spelling and certainly want to get it right, but seen from outside (not knowing etymology or other context), these seem interchangeable. It would be interesting if some eager person could elaborate a bit.