How do you pronounce Elessar?

[Lostgaeriel]

Thank Eru the pronunciation of Elessar has been established beyond any doubt!

But I must, I must, I must clarify Varda's Wilwarin's comment:

I believe nationality plays a part in one's pronounciation dont you? While it is true that what Tolkien says goes, we still have the english saying eg. al-you-min-e-um and the americans saying a-LOOM-inum.

The reason the English pronounce it al-you-min-e-um is because they spell it 'aluminium'. The American spelling is 'aluminum'. Thus the different pronunciation.