What's the difference between "doch" & "mal"?
The words "doch" & "mal" are what German speakers call "modal particles". Modal particles are those little, often monosyllabic filler words in German that usually aren't really translated into English - or at least not directly.
They can change the meaning of a sentence quite drastically. However, more often than not do they give the undertone of a sentences a subtle little twist that can be difficult to pinpoint or explain.
Wo bist du?
Ich bin im Park!