What is YOUR name? Qual é o SEU nome?
your = seu.
What is his name? Qual o nome dele?
His = dele.
What is her name? Qual o nome dela?
Her = dela.
"Seu" can also be "his", "her/hers" and even "their/theirs".
"Teu" is only "your/yours".
This can mean "What is your name?", "What is his name?", or "What is her name?" I put the latter, but it was marked incorrect.
"Qual é o seu nome?" meaning "What is his/her name?" is not more formal than "Qual é o nome dele/dela", it is just uncommon.
Yes, that's perfectly acceptable. However, in Portugal we prefer the expression "Como é que te chamas?" (lit: how do you call yourself)
In portugal, if I don't know the person, should I use "Como é que se chama" instead of the "te chamas"?
is "qual e seu nome? " acceptable? i don't care if it's understood by the contexts. i mean, is it correct?
That would be more like "How is your name?". It doesn't make sense in any of the languages.
They always put a weird emphasis on the "l" sound that I still do not get it.
When an "L" is at the end of a word it is pronounced like a "W" in English. For example: "Brasil" sounds like /Bra-ziw/ and "Qual" sounds like /kwaw/
Does that make sense?
what is your name? qual é o seu nome? qual seu nome? qual é seu nome? como você se chama? você se chama?
The last one is wrong. It would be correct if you suggest what is that person's name. Like "Você se chama Jonas?" and the person will say "Yes, my name is Jonas"/" Sim, meu nome é Jonas" or "No, my name is Pedro"/" Não, meu nome é Pedro".
Not exactly, because you can put an entonation on "chama" to ask again the name of someone that you forgot, or when you say that expecting the person will complete the phrase with his name. The equivalent for this in English would be "Your name is...?" and instead of "Você se chama...?" you can say "Seu nome/Você é...? " too, that has the exactly same meaning.
P.S.: Peter = Pedro = Pietro = Pierre
Why do you need the possesive word 'seu' in addition to the article 'o'? Obrigado
I understand the use of the possessive 'seu" but do NOT understand the need for the article "o".
Yes, but it is better to include it since it is a bit weird a sentence without a verb.