Stand up straight! Look brave!
(Stand up straight! Do not show fear!)
(In fact, the version with tìtstewnga' is grammatically correct. However, in the context in which Varang speaks it, the original version is justified, even if it bends the rules. She wants to say something sharp and punchy, with good rhythm. 'Ur fkivan tstew! is much stronger than 'Ur fkivan tìtstewnga'. And it's perfectly understandable.)

Stand up straight!

They stood there mutely without saying a word.

The People were standing in a circle, singing.

How good is her Na'vi?

That yerik is standing on a high ledge.

Night of Pandora. The forest is full of life. Many creatures and beasts walk, hunt, and fight to survive. Plants glow to give wonderful bioluminescence to the forest. Fan lizards turn, water flows under the blue bioluminescent light. A Na'vi boy walks aimlessly through the forest to feel peace and to see the night's beautiful life. He makes glowing foot tracks on the strong branches of a tall tree. A beautiful skin-blue color fills the sky, the large world stands strong with his siblings and the stars which seem so small. The boy approaches a lake and thinks about the beauty of the world. Eywa smiles upon this one, who is called Zuvo.

He stands himself up.