Yeni bir dilbilgisi konusu olarak “-den beri” ekini tanıtıyoruz; bu ek, bir eylemin yapıldığı zamandan itibaren hâlâ devam ettiğini anlatır.

-den beri literally means “since (that time)” and tells you that an action or state that began at a specific point in the past is still continuing now. You attach it to a time expression to mark the starting point.
Example:
Sabah kahvaltıdan beri kahve içiyorum.
(“I have been drinking coffee since breakfast.”)

1. First add the ablative suffix -den to your noun; then write beri as a separate word.
2. Follow Turkish vowel harmony and consonant assimilation rules:
   
   • If the last sound of the noun is a front vowel (e, i, ö, ü), use -den.
   • If it’s a back vowel (a, ı, o, u), use -dan.
   • After a voiceless consonant you often see a t instead of d (kitap → kitaptan beri).
3. Always separate beri with a space: e.g. sabah
   • -tan
     • beri → sabahtan beri.