Could someone explain and give some examples for when to use the two you´s, sen and siz please. Why is there two you´s that mean the same thing?

"Sen" means "singular you" (just one person), and "siz" means "plural you" (more than one person). For example, you can use "sen" when you talk with a friend (just one friend), and "siz" when you want to say something to a group of people.

Also, in Turkish, if you want to show respect to someone, you address him/her in "plural way" - using "siz" (not "sen").

sen is singular

siz is plural

siz is also used as the singular form when addressing someone ´superior´ or as a sign of respect to your elders similar to the ´tu´ and ´vous´ in French.

Sorry tomac-I hadn´t seen yours when I posted.

Thanks so much tomac and sonunda!