Describe the Houyhnhnm's language?

Gulliver tells the reader that the horses have no system of letters and do not read or write, but that they maintain their knowledge through oral tradition. There are no words in Houyhnhnm language for any of our common human flaws like greed, power, lying, cheat in, jealousy....The closest Master Horse can get to the word "lie" is the phrase "the thing which is not". Gulliver hence has a tough time conversing with Master Horse about the human condition.