Spelling and pronunciation of....

[PrincessC]

I always thought it was pronounced "A Liar"

I think it's quite a popular name too.
I'm not really a fan but it's great that your dp has suggested a name!

[GirlsRock]

I pronounce it Are-lia (same way as your first suggestion) rhyming with Tahlia.

[Mallie]

I have one in my class and it is A-LEE-A spely Aaliyah

[sweetsugardumplin']

My DD's name is Aliah (we changed the spelling hoping to increase the likelihood of people pronouncing her name correctly.......and most do )
It's a beautiful name x

[misskittyfantastico]

I'd pronounce it A-lee-ah.
Arlia, Aliah, Ahlia are some that I know are pronounced Are-lia.

[raisingthree]

I'd pronounce it A - lee- a but if you want to ensure its pronounced the first way then maybe Arlia???