Pronunciation?

[Taronyutsyìp]

Ok this might sound dumb, but how do you know which syllable to put the stress on?  I know in spanish its the second to last syllable unless there's an accent mark...  Is there a rule like that for Na'vi?

[wm.annis]

Ok this might sound dumb, but how do you know which syllable to put the stress on?  I know in spanish its the second to last syllable unless there's an accent mark...  Is there a rule like that for Na'vi?

There is no rule.  You must, unfortunately, memorize the accent for each new word you learn.

In Frommer's documentation, the accent is marked with underlining, although on his blog he uses both underlining and all upper-case (letsim or leTSIM).  In the community dictionary you have to look at the IPA (= international phonetic alphabet), which has a little hatch-mark in front of the accented syllable: [lɛ.ˈʦim].

When a word takes infixes or prefixes, the accent stays on the same vowel that had it before the affix.  With suffixes, that's usually true, but some cause accent shifts.  You can worry about them when you get far enough along in your studies to care about those particular suffixes.

[Taronyutsyìp]

Irayo... or not.  Oh well, I suppose everything can't be that easy...   

['Oma Tirea]

When a word takes infixes or prefixes, the accent stays on the same vowel that had it before the affix.  With suffixes, that's usually true, but some cause accent shifts.  You can worry about them when you get far enough along in your studies to care about those particular suffixes.

True, but there are a couple of exceptions: fra- and kaw-, which have stress.

Other notable exceptions of irregular stress: the tute/tuté contrast, as well as the stress shift in the words omum and inan when (pre-)first-position infixes are added.  Other than that, stress plays a very minor role in Na'vi.