The Scroll from Uncle reads:
You need to know what happened after your great-grandfather’s death,
it can show (you) your fate/destiny
What is interesting is the pronoun choice: 你
你 (ni) mean ‘informal you’, which, since Zuko is the crown prince, would be utterly inappropriate for anyone but family to use.
If anyone but Uncle (e.g. a fire sage, or a servant) had written this, the correct address would be: 殿下 (dian xia) or 王爷 (wang ye) ‘Your Highness’ or at the very least 您 (nin) (formal, polite address for superiors, like the German “Sie” or the French “Vous”.
Fun fact: 尔 (er) is the equivalent archaic ‘thou’ and
亲 (qin) is on the way (at least online) to replace ‘您‘。
How would they refer to themselves: Instead of “I” 我 (wo)
朕 (zhen) - I, the Emperor
寡人 (gua ren) - I, the ruler of a Kingdom
Zuko and Azula:
儿臣 (er chen) - I, your child and subject
本将军 (ben jiang jun) - I, the General