Perfekt vs Präteritum
So i'm confused.
Lots of online lessons say that you have two ways to speak about the past - the written form (seen in Newspapers, books etc) and the 'spoken' form (seen on Twitter, text message, Facebook, letters, speaking).
A site i know goes on to list the following example:
I saw a bird.
Ich sah einen Vogel.
I have seen a bird.
Ich habe einen Vogel gesehen.
My question is....if one is for written language and one is for spoken languages, why is the English translation different for both?
If 'Ich sah einen Vogel' is 'I saw a bird' in written language, then what is the spoken equivalent for 'I saw a bird'?
All i can think is that 'Ich have einen Vogel gesehen' has been literally translated into English, but that when spoken in German it actually means exactly the same thing as 'Ich sah einen Vogel.'
If anyone could confirm this or teach me the difference that would be great.