Question: Is the character for "you" any different for an older person/one who should be respected/one in authority, as opposed to a friend?
Answer: There are two different characters used as equivalents to English "you":
- 你 nǐ ("you")
- 您 nín ("you" in formal contexts)
The latter character, 您 nín, is used when referring to elders, people of authority, and strangers. It's used in Northern China when referring to one's parents, but not in all Chinese-speaking areas.
An interesting bit of trivia, by the way, is that the English word "you" itself also used to be used only in formal situations, as opposed to the more casual sounding "thou". Over time, "you" came to be used so frequently that English speakers stopped saying "thou" altogether. So English used to have honorifics, just like many Asian languages do today!