Duration and 'For/Since/Ago'

English uses a tiny handful of words — "for," "since," "ago" — to cover every way of talking about a span of time, and English speakers reach for them indiscriminately in Turkish. That doesn't work, because Turkish carves the territory up far more precisely. A completed duration ("I waited for two hours") is built one way; an ongoing one ("I've been waiting for two hours") is built another, with the suffix -DIr; "since" a point in time uses -DAn beri; and "throughout / for the whole of" uses boyunca. Sorting these four patterns is the whole job of this page, and the payoff is that you stop sounding like you're translating word-for-word.

Pattern 1: completed duration — bare time noun

To say you did something for a length of time, and that it's finished, the time expression stays bare — no suffix, no preposition — and the verb is in the past. English "for" simply has no Turkish equivalent here; the bare duration is "for two hours."

The action is over and the duration is total: you waited, the waiting ended, it lasted two hours. Adding için "for" here (iki saat için bekledim) is a classic English-driven error — için means "for the purpose of," not "for the duration of."

Pattern 2: ongoing duration — -DIr and the present

Here is the pattern English speakers most often get wrong. When the span is still going — "I've been waiting for two hours (and I'm still waiting)" — Turkish does two things at once: it puts -DIr on the time noun and keeps the verb in the present continuous (or present). The English perfect ("have been waiting") becomes a Turkish present, because to a Turkish ear the action is happening now, with a duration attached.

The suffix -DIr (-dır/-dir/-dur/-dür, devoicing to -tır/-tir/-tur/-tür after voiceless consonants) attaches to the duration and means "for / it's been."

Notice the tense in each: bekliyorum (present continuous), var (present existential), görüşmüyoruz (present continuous negative). The duration is in the past, but the action is present — that's the engine of the construction. Saying iki saattir bekledim (with the past) would clash, because -DIr asserts the action is still live.

There's a second, fixed use of -DIr worth flagging so you don't confuse it: Ne zamandır? "Since when? / For how long?" — the standard question that -DIr answers.

Pattern 3: "since" a point in time — -DAn beri

For "since" — measuring from a starting point rather than naming a length — Turkish uses -DAn beri "since" (the ablative -DAn "from" + the postposition beri "since"). The complement is a point in time (a moment, an event, a clock time), not a duration. See beri, dolayı, rağmen. As with -DIr, the verb stays present, because the action continues to now.

The contrast with -DIr is the crux: -DIr answers "for how long?" (a measured span — iki saattir), while -DAn beri answers "since when?" (a fixed start — saat ondan beri). English uses "since" for the start and "for" for the span; Turkish keeps them in separate constructions, and the question words match: Ne kadar zamandır? "for how long?" vs. Ne zamandan beri? "since when?".

To say "since" before a whole clause ("since I started university"), you nominalize the verb and add -DAn beri: üniversiteye başladığımdan beri. The converb -(y)AlI is a close relative meaning "ever since (doing)" — see the -(y)AlI converb — as in geleli "ever since I came."

Pattern 4: "throughout / for the whole of" — boyunca

When you mean "for the entire stretch of," with emphasis on the whole span being filled by the action, the postposition is boyunca "throughout, all through, for the duration of." It follows a bare time noun (or one with a possessive) and works with any tense.

Boyunca adds an "every moment of it" flavour that bare duration lacks: üç gün bekledim is "I waited three days," but üç gün boyunca bekledim stresses "for three solid days, the whole time." (Boyunca also means "along" with physical length — yol boyunca "all along the road" — the same "full extent" idea applied to space.)

"Ago" — the bare noun + önce

For completeness, "ago" is its own pattern, fully covered on önce / sonra: a bare time noun + önce. It points to a finished moment in the past, so it pairs with the past tense — distinct from the ongoing -DIr and -DAn beri.

So the same English "three years" sits in three different frames depending on meaning: üç yıl önce "three years ago" (finished point), üç yıldır "for three years (and still)" (ongoing span), üç yıl boyunca "throughout the three years" (full stretch).

Putting the four side by side

The single decision that organizes all of this: is the action still going on? If yes, you're in -DIr or -DAn beri territory (present-tense verb). If it's finished, you're in bare-duration, boyunca, or önce territory (past-tense verb).

Common mistakes

The headline error is using one pattern — usually the bare duration or için — for everything English would say with "for."

Key takeaways

• Finished "for" = bare time noun + past: iki saat bekledim. Never için.
• Ongoing "for / have been" = time + -DIr
  • present verb: iki saattir bekliyorum. The English perfect maps to a Turkish present.
• "Since" (a start point) = -DAn beri
  • present: sabahtan beri bekliyorum. Answers "since when?".
• "Throughout / the whole of" = boyunca: gece boyunca uyumadım.
• "Ago" = bare noun + önce
  • past: üç yıl önce.
• The organizing question: is the action still going on? Ongoing → -DIr / -DAn beri (present); finished → bare duration / boyunca / önce (past).