Na'Vi lines in Tirea Tskoyä

[Ikranä mokri]

tslolam sa'nok
I undersatnd Mother

Neytiri kä plltxe jake hu
Neytiri go speak with Jake

sa'nu lumpe plltxe hu tawtute ayli'u
Mum why we speak with sky people words

FTANG FÌFYA
Stop this

are these correct? Over time there will be more and more sentecnces and maybe a speech or 2 on here 

[Ikranä mokri]

*bump*

(cute sad voice) Pwese hewp me people

[Ftiafpi]

Sorry it took so long for someone to get to this.

tslolam sa'nok
I understand Mother

Hmmm, this translates more to "understood, mother" and probably should have a vocative marker in there as well but otherwise is correct.

tsl<ol>am ma sa'nok
understand-PER [voc] mother
Understood mother

Neytiri kä plltxe jake hu
Neytiri go speak with Jake

I'm not sure if what you wrote is wrong but I would put sì in there between "go" and "speak". Also, again, we need a vocative marker here. Otherwise it looks good.

ma Neytiri kä sì plltxe *Jake* hu
[voc] Neytiri go and speak Jake with
Neytiri go and speak with Jake

sa'nu lumpe plltxe hu tawtute ayli'u
Mum why we speak with sky people words

What you've written is "Mum why speak with sky people words" so you would need a "we" in there to say what you translated it as. Also, again you need a vocative marker and you also need an infix in "speak" to mark a tense or aspect (depending on what you're trying to say). If you want to say "why are we speaking" then you need the imperfective infix. If you want to say "why did we speak" or "why were we speaking" then you would need the perfective infix or past tense inspect respectively. I'm going to assume you wanted present perfective for the tense and aspect (infix is <ol>). Finally, you need a genitive (possessive) suffix on "sky people" to denote that it's their words.

Also, hu denotes accompaniment. You want fa which is "with or by means of". Don't forget that speak is transitive so you need the ergative affix now that we're using a pronoun. I don't believe we need an accusative affix on "sky people's words" but I could be wrong.

ma sa'nu, lumpe oeng-l p<o>lltxe fa tawtute-yä ayli'u?
[voc] mom, why 1-DUAL-ERG speak-PER with sky people's words?
Mom, why did we speak with sky people's words?

Note that the 'l' drops off the <ol> infix since you can't have 'lll' in Na'vi.

FTANG FÌFYA
Stop this

fìfya means "this way or like this" and comes from fì (this) + fya (path or way). You want fìkem meaning "this (action)".

Ftang fìkem!
Stop this (action)!
Stop this!

Note: in the movie Neytiri says "ftang nga!" (stop you!) twice, this may be a "better" way of saying this.

[Ikranä mokri]

irayo for ypu help

its needs to be stop this for the plast as the character is having the crap beaten into him by a group of Na'Vi