Researchers who study bovine behaviour have recently discovered that cows, like humans, have different regional accents. Cows in a small herd may all sound very similar, while the same species on the other side of the country or in another country may have their own distinct accent. This phenomenon has also been observed in birds. In English, the word used for a cow sound is “moo”. This type of word is onomatopoeic. The naming of the word is based on the sound that the word makes. Words like “boom”, “tweet” and “pop” are all examples of onomatopoeia. In many languages, people use the word “moo” or something very similar to vocalize the sound of a cow. This is not the case for other animals, such as pigs. In English a pig says “oink”, while in other countries it says “boo-boo”, “oof”, or “heh-roo”.