We are talking about T-V, not TV. There is a distinction.
T-V Distinction
What is the T-V Distinction?
Wikipedia tells us:
T–V distinction (from the Latin pronouns tu and vos) is a contrast, within one language, between various forms of addressing one's conversation partner or partners that are specialized for varying levels of politeness, social distance, courtesy, familiarity, age or insult toward the addressee.
[I like the insult reference, as it applies to French. See below]
The term T-V comes from the two Latin personal pronouns for the second person: singular tu and plural vos. In personal pronouns, the second person or group of persons is the one being addressed.
In Latin, when you addressed one person, you would use "tu", even if it was a high ranked person, and "vos" for a group of persons.
At some point, starting in the fourth century, the plural started to be used when addressing the Roman Emperor, then the Pope, then more and more "important" people.
This is reflected in many romance languages such as French.
However, there are many differences between English and French related to the T-V distinction.
English
In Old English, it was easy: to address a single person, use "thou"; to address more than one person, use "ye".
In Middle English, under the influence of Norman French, gradually "thou" was replaced by "ye" when addressing a superior person, then an equal.
However, in the XVIIth century, the use of "thou" declined rapidly, and it was considered as impolite to address somebody as "thou" (insulting maybe?).
So, in modern English, there is no longer any real T-V distinction. To address anybody, use "you".
It is only in rare circumstances that "thou" is used, mostly to address God.
French
In French, a similar evolution of the uses of "tu" (singular) and "vous" (plural) occurred, but did not go as fas as in English, and in most French speaking countries, there still is a rigid T-V distinction. French Canada is an exception.
When addressing a single person, "tu" is informal and "vous" is more formal.
You would use "vous" to address a superior (at work for example), someone in a business transaction (in a store or at the bank) or some unknown adult that you just met.
You would use "tu" to a child, somebody of your family, a lover, a colleague you work with every day that is not your superior.
When you meet someone for the first time (a neighbor , for example) you would start with "vous", then if you meet regularly and appreciate each other, you would "negotiate" to use "tu".
There are cases when the use of the pronoun is not symmetrical. For example, an adult that meet a child for the first time would most likely use "tu" to address the child, but the child would use "vous" to the adult.
When people meet for the first time and start dating, they often use "vous", then after several dates, switch to "tu".
In movies and TV series, even when translated from English, the switch to "tu" often happens after they first make love.
When two people start to fight verbally, even when they would normally use "vous", they often switch to "tu" to insult each other. I have a hard time imagining using "vous" when insulting somebody (that I tried to avoid, of course, but you never know when you are too angry to resist).
In my family, I have seen two unusual cases of T-V distinction, according to current culture:
my parents used "tu" to address their children, but us children we used "vous" to address our parents. This was common practice in the first half of the twentieth century, but it has almost completely disappeared. Nowadays, children use "tu" to their parents.
my uncle Charles, a brother of my father, and his wife, my aunt Béatrix, never switched to "tu". They continued until the end of their common life to address each other as "vous". This is the only case I know of married people that did that.
If you have read up to this point, you may appreciate this French tongue-twister:
- Saucissier sans soucis, combien ces six saucisses-ci?
- Six sous!
- Six sous, saucissier sans soucis? Ces six saucisses-ci sont trop chères.
