When a person makes a blunder, you could say he "put his foot in his mouth".
That expression is rather old and maybe they don't teach that in schools anymore.
So perhaps it is timely to introduce a new expresssion.
How about "cow-head disease" for people who simply do not know how to express themselves properly?
If you read the 60 plus opinions expressed in this malaysiakini article in which the MCMC deputy minister claims public expect action, the ordinary folks are telling this poor chappie that he has "cow-head disease" or a more virulent strain.
MOO, MOO Minister!