"English is the international language."
Translation:Τα αγγλικά είναι η διεθνής γλώσσα.
That's just how it is for all languages in Greek. The other option is to say 'the English language' - 'η αγγλική γλώσσα'.
It's similar in French, except they use the masculine form for the short version: le français/japonais or la langue française/japonaise etc.
Edit: You can also drop 'γλώσσα' and say 'στην αγγλική' but it is rather formal and old fashioned.
As an aside, I was listening to a podcast about Greek and the presenter said that a Greek speaker who doesn't have strong English might be heard saying "I don't speak THEM very well" referring to English - this is because of the way languages are expressed in plural!
Yes, same with referring to hair in plural because it is μαλλιά (neut., plural) in Greek.
i believe that "τα αγγλικα ειναι η παγκοσμια γλωσσα" is correct as well because global and international tend to have the same meaning.