Negation in Turkish is primarily achieved using suffixes or specific negative words.

1. Negating Verbs with -me/-ma:

The most common way to negate verbs is by inserting the suffix -me or -ma (A-Type vowel harmony) after the verb stem and before tense/mood and personal suffixes.

• geliyorum (I am coming) → gelmiyorum (I am not coming - -me- changes before -iyor)
• yaptım (I did) → yapmadım (I did not do)
• okuyacak (he/she will read) → okumayacak (he/she will not read - buffer 'y')

The negative suffix for the Aorist (Simple Present) tense is slightly irregular for some persons (e.g., gelmem - I don't come, gelmez - he/she/it doesn't come).

2. Negating Nouns and Adjectives with değil:

To negate predicative nouns or adjectives (sentences like "X is Y" or "X is not Y"), the word değil (not) is used. Değil follows the noun/adjective and takes any personal or tense suffixes.

• Bu bir kitap. (This is a book.) → Bu bir kitap değil. (This is not a book.)
• Hastayım. (I am sick.) → Hasta değilim. (I am not sick.)
• Öğretmendi. (He/She was a teacher.) → Öğretmen değildi. (He/She was not a teacher.)

3. Existential yok (not exist / there isn't):

The word yok is used to express non-existence (see Existential Sentences section).

• Evde kimse yok. (There is no one at home.)

4. Double Negatives with ne ... ne (de) ...:

The conjunction ne ... ne (de) ... (neither ... nor ...) is used with a POSITIVE verb form to convey a negative meaning.

• Ne çay ne (de) kahve içti. (He drank neither tea nor coffee. - literally "He neither tea nor coffee drank.")