Depending on the context, اي and شي can both mean “some” or “any” in Arabic. When talking about “some” or “any” plus a noun (human or non-human), we say "اي اسم" or "شي اسم". In general, the two words are interchangeable in this context, but there are a couple common exceptions. Notably, when saying the specific phrases “some person” or “any person” and “anything,” you must use اي. For example:

اي شخص يلي شفته مبارح
Some person who I saw yesterday

ما بدي اي شي منك
I don’t want anything from you
"ما بدي ولا شي منك" Though you could also say

Now let’s look at some examples where either اي or شي can be used. All of these sentences appear in song lyrics we have previously posted about on Fi Kalam, so click on the name of the song if you want to read and hear it in context.

From the song Kezbak Helow by Mayada Basseliss:
شو حلو لما كنت شي كذبة بحياتك
How nice it was when I was just some lie in your life
We could also say:
شو حلو لما كنت اي كذبة بحياتك

From one of my favorite love songs, Shim el Yasmine by Mashrou' Leila:
بس انت ببيتك وانا بشي بيت
But you’re in your house and I’m in another house
We could also say:
بس انت ببيتك وانا باي بيت

From the song Majnoon by Yazan Haifawi:
نحن مش اي تنين
We aren’t just any two [humans]
We could also say:
نحن مش شي تنين