If you speak a lot to native German speakers, especially from the south, you may find the definite article used with proper nouns :)
It's colloquial, though, and possibly considered slightly sub-standard. (But people don't always speak Standard Written German, of course: sub-standard need not mean "bad", just not something you'd use in an academic paper or the like.)
Hast du den Klaus gesehen? - Ja, der steht dort drüben bei der Maria.
Sometimes that you should note is that in Greek we use articles before names, cities, countries, etc. too. In English you would never say something like " The Chris" but in GREEK you will say ' Ο Χρήστος' you would never say 'The Greece' but in Greek you will say " Η Ελλάδα" wouldn't you, because its the Greek language. Its the way of identifying them is by their definite article. Cheers!!!!
Just to clarify something When talking in everyday/casual Greek you can just say Είμαι η Ελένη and Not include Ι(εγώ) Not saying that saying Εγώ είμαι η Ελένη is wrong, it would sound weird in proper speech If you want to introduce yourself formally you could say “Με λένε - insert name here-" which would translate to they call me - insert name here- Normally when speaking in Greek you don't often see people use more than those two expressions to introduce themselves
P.S: you might see Εγώ είμαι η Ελένη written down as to emphasize the fact that that you are not just anyone but you are THE -insert name here-. But in speech it is rarely used
You skip the article, because your name is the word "Eleni", not the person Eleni.
η Ελένη is the person bearing that name
Ελένη is the word itself, the name itself
Thus Εγώ είμαι η Ελένη (I am [the person] Eleni) but Με λένε Ελένη (They call me [by the name] Eleni).
Why is 'I am the Eleni' wrong?
Because in English, we don't use "the" with names of people.
We say "I am John" and not "I am the John".
We say "Talk to Paul" and not "Talk to the Paul".
And so on.
So when translating from Greek into English, η Ελένη turns into "Eleni" -- not "the Eleni".