Conditional sentences express a condition and its consequence. They typically consist of an "if" clause (the condition) and a main clause (the result). In Turkish, the conditional mood suffix -se/-sa is key to forming these.

The conjunctions eğer or şayet (if) can be used at the beginning of the conditional clause for emphasis but are often optional.

Type 1: Real/Possible Conditions (Present/Future)

This type refers to conditions that are likely or possible to happen in the present or future.

Structure: (Eğer) [Verb + Aorist/Future + -se/-sa + Pers.Suffix], [Main Clause (Aorist, Future, Imperative, etc.)]

• (Eğer) zamanım olursa, gelirim. (If I have time, I will come.) (Aorist in both)
• (Eğer) yarın yağmur yağarsa, evde kalacağız. (If it rains tomorrow, we will stay at home.) (Aorist + Future)
• Çalışırsan, başarırsın. (If you study, you succeed/will succeed.)

Type 2: Unreal/Hypothetical Conditions (Present/Future)

This refers to conditions that are unlikely or contrary to fact in the present or future. Often, the main clause uses a past form of a modal or future.

Structure: (Eğer) [Verb + -se/-sa + Past Suffix (-ydi/-ydı) + Pers.Suffix], [Main Clause (often Aorist + -di, or Future + -di)]

This often looks like: Verb Stem + -seydi/-saydı + Personal Suffix for the "if" clause, and Verb Stem + Aorist + -di + Personal Suffix for the result clause.

• (Eğer) zengin olsaydım, bir ev alırdım. (If I were rich, I would buy a house.)
• Senin yerinde olsam, öyle yapmazdım. (If I were in your place, I wouldn't do that.) (Note: Present conditional for "if I were")

Type 3: Unreal Conditions (Past)

This type refers to conditions in the past that did not happen, and their hypothetical past results.

Structure: (Eğer) [Verb + -miş olsaydı / Verb + -seydi], [Main Clause (often Aorist + -di or Future + -di or -miş olurdu)]

• (Eğer) çalışmış olsaydın / çalışsaydın, sınavı geçerdin. (If you had studied, you would have passed the exam.)
• Daha erken gelseydik, treni kaçırmazdık. (If we had come earlier, we wouldn't have missed the train.)

The combinations can be complex, but -se/-sa is the core conditional marker.