Windmills can't say much but they do have a primitive language:   

+ made by the vanes mill at rest, ready for operation 
x made by the vanes temporarily out of service or not needed 
tilting slightly to the left: mourning 
tilting slightly to the right: a happy event 
sails decorated with flags, etc., a festival or celebration   

During WW II a similar signalling system used by the Dutch resistance 
indicated to the English planes flying overhead whether or not it was 
safe to make a drop.