Wut's up bro? Cuz?

It was set to be released originally in 2020. So working backward, there was postproduction. Working further backward there was the time spent filming. Then finally, before all that the script was written.

So the language used was how Cameron thought kids spoke -- in what -- 2015? 2017? 2016?

But to your point, it's a bit dated now.

I'm no expert, but I think kids now say "bruh". . . not "bro."

I could be wrong.

As to your observation: "This isn’t how intelligent/educated people talk, let alone Navi people raised in a traditional tribe!"

The Navi were not "educated" people in the sense we think of educated. And remember, Jake's kids were raised by Jake, so we are meant to think his influence affected their language, attitude, etc.

I agree it was cringey, but briefly and momentarily. For a 3 hour film these cringe moments evaporated as soon as they appeared, for me at least.

This film is clearly made for kids. with most focus being placed on kids as well - and from what I gather, studios don't bother with quality scripts much these days - kids will eat this shit up either way.

One reviewer noted that this film feels like it was written by AI - I have to agree - Alas, I suspect the first film was also written by AI - I can even imagine what keywords Cameron might have used when asking AI to come up with script. These films feel like mishmashes of other films in blue setting on another planet. If AI is good for anything, it's taking previously created scripts and combining them together to create something new -

This is precisely what Stargate is doing these days - https://www.syfy.com/syfy-wire/stargate-reunion-crossover-ai-script

Yes in reality it is horrendous!
Reality is horrendous!
7 billion overpopulation and 4 billion are teletubby-retarded Trash Millenials! Earth could be paradise if everyone started in his own mirror instead of stupid herd mentality. Who needs dumb kids to constantly look after?!?? For about TWENTY (!!!) years instead of 6-9 weeks like most superior species! Nothing positive on CHILD MADNESS! Zero. Nada. Least for one own. But the Biggest Picture of Mother Earth/Natural Balance is indiscussable!

Those fictional brats sucked over the top. Surely it was cringe! Just another Eeeewwww!
The original Na'vi Portrayal was elaborate and wise. Way beyond our elite as portrayed with Dr. Grace! They should have stuck to that pattern and not incorporate retarded human children behaviour. Dull Jake may be the Father, but they are raised in Na'vi Surroundings by entire tribe. The lenghty mobbing was almost unbearable and a insult for each adult with at least even average IQ.
Trash Millenial youth have no role models. Heck they ever cheered for Shitney Spears as if she was Michael Jackson & Prince & Whitney Houston combined! We don't even get started on Tschassdin Weeeener and Kim Asshole. This movie feeds into their ongoing degeneration. On way more levels than plain in sight. Dumbest generation of all Times will make sure on WW3. Destroying 5000 yrs of progress. Back to stone-age. A bit natural tribe like just without all the fancy stuff and real spirit/IQ.

Agree it was very cringeworthy. As far as I'm aware there's not even any characters on this planet that talk this way to influence them into speaking like that. Is there a Navi clan that are a bunch of surfer dudes that they hang out with or something?

If they had spent more time giving the older brother more meaningful dialogue than "bro" and "cuz" it may have made his death more impactful for me.

I call people bro and cuz.

Never mind "bro" and "cuz", what about Neytiri's constant "My Jake"s? This was even in the first movie!

Bro is what people say when they lack a vocabulary to say anything else