"Cow" is generally spelled in English as kao or kaao.
It means: white, rice, he, she, they, to enter, horn, hill or small mountain, news, and fishy smell.
It also has many other meanings when used with other words or in compund words, such as "gin kao" means "to eat food," and "kao jai" means to understand, and "kao leu" means rumor, and "puu aan kao" means "TV news anchorman."
Obviously, these words are pronounced with different tones, and differences in how fast the word is said, i.e., short and abrupt pronunciation as opposed to longer, slightly more drawn-out pronunciation of the vowel sound.
To a Thai person, when a word is spoken with a different tone, even though to us it sounds the same, to them it sounds completely different. Often, even people who speak English and talk to farangs all day long, don't have a clue as to what you are saying when you get the tone wrong!
In my Thai class, many times when one student is speaking Thai, the teacher can't understand, even though I understand every word, and I end up translating it for her. Because I speak with the same horrible American accent, it is easy for me to understand him, but the teacher many times can't!!!!!