Dead men tell no tales

This problem is more like a funny story then a real problem.

In Numberland there are four tipe of men: humans, dwarfs, zombies and ghosts.

There are a human and a dwarf , that are living, a zombie , that it isn't dead, and a ghost , that is dead.

• When the man say "0" , the others be silent.
• When the man say "1" , the dwarf say "2" .
• When the man say "2" , the dwarf say "4" and the zombie say "6" .
• When the man say "3" , the dwarf say "5" , the zombie say "7" and the ghost ...

What we can suppose the ghost say??

An help: read all the text of the problem... I say all!