For example:
Große Bäume
but
Die großen Bäume
or
Lange Leitungen
but
Die langen Leitungen
Why is the an n at the end if there is "Die" in front of it? Both are plural and both are nominative, right? What's the difference?
For example:
Große Bäume
but
Die großen Bäume
or
Lange Leitungen
but
Die langen Leitungen
Why is the an n at the end if there is "Die" in front of it? Both are plural and both are nominative, right? What's the difference?
So you're describing the situation between having an article and not in the plural. Case is used to show different parts of speech clearly. If you remember that when you have the feminine article "die", this is always followed by the "-e" ending. To create a distinction, the "-en" came about to show that it isn't feminine singular - to add more clarity in exactly what is being said. The reason it doesn't have this without an article is so that there are options to demonstrate cases like the dative and genitive clearly.
Long story: To create more distinction between cases and singular/plural
Short story: Because it is how German has developed.