Jean-Jacques Rousseau Rousseau

This a French question, not an English one.

First names are written with a hyphen when one wants to make them a single first name:

Jean-Jacques, Jean-Pierre, Jean-Louis are single first names.

Jean, Jacques, Pierre, Louis are single first names.

Same in German: with hyphen considered to be one first name: Karl-Heinz.; without two names: Johann Wolfgang

Can't we let the girls have a look-in? Marie-France and Anne-Sophie's mutter are feeling a bit left out.

Yes, we can. I know a German lady whose name is Anne-Rose..

disambiguation:

Marie-France (and Anne-Sophie's mutter)

The humorist and philosopher Eau-Badoit San Pellegrino once remarked: "My hyphen is there for all the world to see, but I trust that my colon shall remain hidden".

If this isn't off-end: I read a report by Apollo-Naris some time ago, his-story about hyp-hens .... your above quote was mentioned there as well.

But why a hyphenated first name?
But my question is why these people have been given such hyphenated first names? Am I right to say that one of the reasons is probably a hyphenated first name is given in memory of someone? ...

Nobody knows "why" some French people have compound given names. It is just a custom, whose origin is lost in the mists of antiquity. It is nothing to do with language or English, as you have been advised. Americans in the southern part of that country are sometimes called Bobbie-Jo or Jimmy-Joe. There is no "reason" for it in the sense that you seem to mean.

Jean-Jaques ("John-James"), know simply as "Ji-Ji" to his playmates while still a child, was raised by a gay couple who had hired a common street walker upon whom to sire a child to honor their informal union.

He was named for both of his fathers.

I don't know why Setanta inserted that mischievous and childish nonsense. The truth is actually more interesting and racy.

Rousseau was born in Geneva, Switzerland, in 1712. Nine days after his birth, his mother Suzanne Bernard Rousseau, died of complications. To avoid imprisonment, his father Isaac, a failed watchmaker, abandoned him in 1722. His childhood education consisted solely of reading Plutarch's Lives and Calvinist sermons. According to Rousseau's account in Book I of the Confessions, his experience of corporal punishment at the hands of his pastor's sister was important in the formation of his sexuality.

After several years of apprenticeship to a notary and then an engraver, Rousseau left Geneva March 14, 1728. He then met a French Catholic baroness named Françoise-Louise de Warens. She was thirteen years older and later became his lover. He had a birth defect of the penis called hypospadias.

I inserted it because it entertained me. The actual mischievous and childish truth is far less entertaining, to my mind.

I forgot to add:

I had planned, had anyone asked, to point out that i made a completely ridiculous response, because there are times when i tire of the pointless questoins of Chinese students of English, upon which they insist, as though the answers were important, when patently, they are not.

I have to say, setanta, that I am in complete agreement with you, and I apologise for my earlier attitude. I fear we are banging our heads against a brick wall however.

Set, why would it occur to anyone to ask about the norm?

Ah well, it's only a virtual wall, so it will only produce a virtual headache.