What Causes Echo Of What I Speak?

After i speak I hear back what i have just said loudly in my own voice. This can happen the second after i speak or sometimes 30 seconds to a minute after. Sometimes I think it is inside my head and other times I hear it so loudly I wonder if it is from outside. It makes me think did i say that again (i realise that i havent ) as it is an exact echo of what i have just said. Its like i have been recorded and its bejng played back a second later. This is very worrying and annoying. Its not like a compulsion i feel like i need to do . It just happens automatically.