Greek has two different words to negate a statement being made in a sentence.

In Greek, individual words can be negated by prefixing the letter 'alpha' (called the alpha privative). If the word being negated begins with a vowel, the letter 'nu' is inserted between the alpha privative and the first letter of the word. This is done to prevent the contraction of vowels, which often occurs in Greek when two vowels come together.

English shows the influence of this Greek feature in many of its words: