"Vâng, thuyền trưởng!"
From Chinese 船長 chuánzhǎng (Cantonese syun4zoeng2).
Note that this means specifically a ship’s captain: 長 means ‘head of’*, and 船 means ‘ship’.
*It’s pronounced chou in Japanese; if you watch Japanese media you might here the terms 社長 shachou ‘head of company, CEO’ or 部長 buchou ‘head of department’.
It's the word "trưởng" that carries the meaning "head of something" (department, company...).
I'm curious why the head of a country is not "quốc trưởng" (元首) since it is always dedicated for Hitler's title.
What do you mean? Quốc trưởng (國長) and nguyên thủ (元首) are two different words, and none of them is the translation of Führer in Vietnamese.
The 'th' of 'thuyền trưởng' sounds like a 'p' to me, no matter how often i am listening to it. Anyone else hearing it like that?
And this is how sound shifts in languages begin—a bunch of people thought it was another sound. Language is just a never-ending game of telephone.