Elapsed time since an action (-alı, -eli)

To express how much time has passed or how things have changed "since" an event, Turkish uses a single verb suffix.

The Elapsed Time Suffix: -(y)AlI

To say "since doing [action]" or "since [event] happened," attach the temporal suffix -(y)AlI to the verb stem.

Following two-way vowel harmony, the suffix is either -alı or -eli. If the verb stem ends in a vowel, use the buffer -y- (-yalı / -yeli).

Pair it with a time expression and oldu (it has been) to state how long it has been since an event:

It has been five years since we moved to this neighborhood.
Biz bu mahalleye taşınalı beş yıl oldu.

Describing Changes

Use -(y)AlI to set a milestone in the past and describe how a situation has transformed since then:

The neighborhood has changed a lot since the subway opened.
Metro açılalı mahalle çok değişti.
The population of this city has increased a lot since the hospital opened.
Hastane açılalı bu şehrin nüfusu çok arttı.

The verb with -(y)AlI sets the anchor in time, while the main verb describes the change:

The streets have become wider since the old structures were demolished.
Eski yapılar yıkılalı sokaklar daha geniş oldu.

You can use this structure to contrast how a place used to be with what it has become:

This neighborhood was apparently quiet before, but it has become very noisy since the population increased.
Bu mahalle önce sessizmiş ama nüfus artalı çok gürültülü oldu.