how can you differentiate dog barking?

personally my dog barks 24/7, if my neighbour makes a noise if somebody walks past the house or sometimes he just barks to himself ! But after a while i started to recognise when it was an angry bark or a friendly bark, i knew it was a nasty bark when someone walked past the house and in his fury he jumped through the window !! (no panique he's fine ...) So really my point is if you watch you're dog you're recognise certain barks.

No one in my house can differentiate it. We just know there is something when our dog bark, maybe someone come to our house, stand in front of our house (my dog work as house alarm...), or they are angry toward someone.

I think it is a case of knowing the particular dog, it doesn't take long to get used to their different sounds, from a whimper, a howling, an angry bark, I think it really depends on the dogand circumstances.

They say the same thing about babies, I personally could never tell the difference with a dog or a baby. When he barks try giving him food, and if he doesn't want the food try letting him outside. Just pay attention each time and note to yourself how each bark specifically sounded (perhaps write it down).