Why do dogs bark?

Last night I was dreaming that why dogs barkes...are they mad or barkes only on strangers.

They bark like we speak. It is their way of communicating.

I swear to god my dog barks because the grass is growing...it also depends on what kind of dog you have

BECAUSE THEY ARE TRYING TO TELL YOU FU^K ME! BUT THEY DONT KNOW ENGLISH, SO ALL THAT COMES OUT IS BARK BARK