This is the canon of known good sentences in Na'vi, given out in interviews with Dr. Frommer. Let's keep this page focused on just these, and save further grammatical analysis for the forum or other pages. I assume (and hope) this post will be mostly useless once we get a much fuller grammar.
From Science Magazine (subscription, I'm afraid; retrieved Dec 21 2009). They asked for the word for "science." Frommer replied, tìftia kifkeyä, the study of the physical world.
Language Log Blog Post
From his Language Log guest blog post (Dec 19 2009).
Oeri ta peyä fahew akewong ontu teya längu. My nose is full of his alien smell.
In the comments: Tewti, ma Prrton! Plltxe nga nìltsan! Wow, Prrton. You speak well.
Brushing up on the Language of Avatar (Dec 1 2009)
Kaltxì. Ngaru lu fpom srak? Hello, how are you?
interview (December 12 2009)
Tsun oe ngahu nìNa’vi pivängkxo a fì’u oeru prrte’ lu It’s a pleasure to be able to chat with you in Na’vi
Fìskxawngìri tsap’alute sengi oe I apologise for this moron
Fayvrrtep fìtsenge lu kxanì These demons are forbidden here
UGO Movie Blog
interview (Dec 14 2009)
Oel ngati kameie I see you.