Note that the word for bye in Esperanto is ĝis. This is short for ĝis la revido, which literally means until the re-seeing. So, ĝis actually means until, but by itself means bye.
WHY IS IT "DANKON" AND NOT "DANKO"?
When you use an expression like “Thanks” in English you are actually shortening a full statement. As you will soon learn in Esperanto, -n indicates the object of the sentence as you can see in the examples below:
Dankon = Mi donas al vi dankon.
Thanks = I give you thanks. ("thanks" is the object of the sentence).
Saluton! = Mi donas al vi saluton.
Hi!/Hello!/Greetings! = I give you greetings. ("greetings" is the object)
Feliĉan novan jaron! = Mi deziras al vi feliĉan novan jaron!
Happy new year! = I wish you a happy new year! ("happy new year" is the object)
Kiu means "which person or thing". When used in relation to a person, it usually translates to "who".
People who speak Esperanto generally use their own names, but sometimes choose a name that is easier to pronounce in Esperanto, or an Esperanto nickname. Names for men in Esperanto generally end in -o, and nicknames in -ĉjo. A man named David could decide to use David, Davido, or the nickname Daĉjo. For a woman, Esperanto names can end in -o or -a, and nicknames end in -njo. A woman named Susan could use Susan,Suzano, Suzana, or the nickname Sunjo.