The goat makes a bleat sound, which sounds like a 'maa-maa'. They can make these sound different, according to how they feel, or what they want. You can find more information here: http://www.goats4h.com/GoatSounds.html
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The name of the sound a goat makes is a bleeting noise. They make a noise that sounds like 'Baaaaa' and it is described as a bleet. Goats are vocal creatures and make this sound often.