The verb of ability, equivalent to "can" or "to be able to" in English, is formed using the suffix -e / -a (A-Type vowel harmony) added to the verb stem, followed by the verb bilmek (to know), which is then conjugated in the desired tense/mood.

Formation:

Verb Stem + -e/-a (buffer 'y' if stem ends in vowel) + bilmek (conjugated)

• yap- + -a- + bilmek → yapabilmek (to be able to do)
• gel- + -e- + bilmek → gelebilmek (to be able to come)
• oku- + -ya- + bilmek → okuyabilmek (to be able to read)

Examples in Different Tenses:

• Present Simple (Aorist): Ben Türkçe konuşabilirim. (I can speak Turkish.)
• Present Continuous: O şimdi gelebiliyor. (He/She can come now.)
• Past Simple (-di): Dün yüzebildim. (I was able to swim yesterday.)
• Future: Yarın sana yardım edebileceğim. (I will be able to help you tomorrow.)

Negation of Ability:

The negative form ("cannot", "not able to") is formed with -eme / -ama added to the verb stem, followed by the personal suffixes for the desired tense. The bilmek part is dropped in the common negative form.

Verb Stem + -eme/-ama + Tense/Mood Suffixes + Personal Suffixes

• yap- + -ama- + -m (Aorist 1st person) → yapamam (I cannot do)
• gel- + -eme- + -z (Aorist 3rd person) → gelemez (He/She cannot come)
• oku- + -yama- + -dı + -m (Past 1st person) → okuyamadım (I could not read)

A less common, more formal way to negate ability is to negate bilmek: yapamayabilirim (I may not be able to do), but yapamam is more direct for "I can't do".