Yağmur planı mahvetti.

The rain ruined the plan.

Breakdown of Yağmur planı mahvetti.

• plan: the plan
• yağmur: the rain
• mahvetmek: to ruin; destroy

Questions & Answers about Yağmur planı mahvetti.

Why is it planı, not just plan?

Because planı is the definite direct object form.

In Turkish, a specific direct object often takes the accusative ending:

• plan = plan
• planı = the plan / that specific plan as the object

So in Yağmur planı mahvetti, the speaker means a particular plan was ruined.

A useful contrast:

• Yağmur planı mahvetti = ...ruined the plan
• Yağmur bir plan mahvetti = ...ruined a plan

Since plan ends in a consonant, the suffix is added directly: plan + ı = planı.

What exactly is mahvetti grammatically?

mahvetti is the verb mahvetmek in the past tense, 3rd person singular.

Breakdown:

• mahvetmek = to ruin
• stem: mahvet-
• past suffix: -ti
• mahvetti = ruined

This is the common -DI past in Turkish, often used for a completed past event.

Also, the double tt is normal:

• stem ends in t
• suffix begins with t
• so you get mahvetti

Why is the verb at the end of the sentence?