Hi my 11 month old irish wolfhound has started to take a dislike to people when they stop to comment on him he lunges at them barking and he has tried to grab someones hand, i can be talking to them for a while and out of the blue he just goes mad at them for no reason.this has only started within the last 2 weeks could someone give me some tips on how to deal with him.

Has he had a health check to make sure a health problem is not to blaim for the sudden behaviour change?
Has he had a bad experience reasontly? Anything changed in his life?

As above and also, I would not stand talking to them for any length of time while you get to the bottom of it.  Often in such a situation with a worried dog, the dog will be able to cope with a short encounter but as the encounter gets longer, they become more stressed with being unable to leave until as you've seen, that stress gets the better of them and they react.  So better to just say hello then carry on, so he doesn't find himself trying to deal with more than he can cope with.

Pair these brief encounters with something he likes (meaty treats often work well) and you'll be starting to make them a source of something pleasant, rather than stress.