Learn Hardcore Turkish: Bu küçük hata önemsiz. - This small mistake is unimportant.

Turkish often leaves out the verb “to be” in the present tense for third person. This is a nominal sentence: the subject is Bu küçük hata and the predicate (what it “is”) is önemsiz.

Bu küçük hata önemsiz. = “This small mistake is insignificant.”
You only add a visible copular element if needed for formality or other tenses/persons (see below).

Can I say önemsizdir here? What’s the nuance?

Yes: Bu küçük hata önemsizdir. is correct. The suffix -(d)ir adds a formal, matter‑of‑fact, or generalizing tone (often used in writing, definitions, or statements of general truth). In casual speech you usually drop it:

Neutral/casual: Bu küçük hata önemsiz.
Formal/authoritative: Bu küçük hata önemsizdir.

What’s the difference between Bu küçük hata and Bu küçük bir hata?

Bu küçük hata = “this small mistake” (a specific mistake you’re pointing to). Here bu is a demonstrative determiner modifying the noun.
Bu küçük bir hata. = “This is a small mistake.” Here bu is a pronoun (“this”), and bir is the indefinite article “a.” Don’t mix them as Bu küçük bir hata önemsiz; say either:
Bu küçük hata önemsiz. (This small mistake is insignificant.)
Bu önemsiz bir hata. (This is an insignificant mistake.)

What’s the grammatical structure here?

It’s a nominal (copular) sentence:

Subject noun phrase: Bu küçük hata (“this small mistake”)
Predicate adjective: önemsiz (“insignificant”) No explicit “is” is needed in third‑person present.

Why is there no case ending on hata?

Subjects are in the bare (nominative) form in Turkish. Case endings appear when the noun has a different grammatical role. For example:

Accusative object: Bu küçük hatayı görmüyorum. (“I don’t see this small mistake.”)
With a verb of opinion: Bu küçük hatayı önemsiz buluyorum. (“I find this small mistake insignificant.”)

What exactly is önemsiz? How is it formed?

Önemsiz is an adjective meaning “insignificant/unimportant.” It’s built as:

önem (“importance”) + -siz (“without”) → “without importance.” The suffix varies by vowel harmony: -sız/-siz/-suz/-süz. Other examples:
parasız (without money), tuzsuz (unsalted), şekersiz (sugarless).

How do I negate this idea?

Two common options:

Bu küçük hata önemsiz değil. = “This small mistake is not insignificant” (i.e., it might actually matter).
Bu küçük hata önemli değil. = “This small mistake is not important.” (more neutral/softer) Another idiomatic option: Bunun önemi yok. = “It doesn’t matter.”

Can I move önemsiz to the front for emphasis?

Yes, fronting the predicate adds emphasis:

Önemsiz bu küçük hata. (Emphasizes “insignificant.”) Default, neutral order keeps the predicate at the end: Bu küçük hata önemsiz.

How do I ask a yes/no question with this?

Use the question particle after the predicate:

Bu küçük hata önemsiz mi? (Is this small mistake insignificant?) Negation + question:
Bu küçük hata önemsiz değil mi? (Isn’t this small mistake insignificant?) If you want “Is this a small mistake?” use the “bir” pattern:
Bu küçük bir hata mı?

How do I make it plural?

Bu küçük hatalar önemsiz. = “These small mistakes are insignificant.” You can add -(d)ir for formality: Bu küçük hatalar önemsizdir. Avoid putting plural -lar on the adjective here; you don’t say önemsizler with non‑personal noun subjects like “mistakes.”

How do I put it in past or future?

Past: Bu küçük hata önemsizdi. (was insignificant)
Reported/inferred past: Bu küçük hata önemsizmiş.
Future: Bu küçük hata önemsiz olacak. (will be insignificant) Turkish uses tense/evidential suffixes or the verb olmak with adjectives for non‑present meanings.

What’s the difference between bu, şu, and o?

bu = this (near the speaker)
şu = that (near the listener or mid‑distance)
o = that (far from both) and also “he/she/it” So you could say Şu küçük hata önemsiz. or O küçük hata önemsiz. depending on distance.

Is küçük the only way to say “small”?

No. Common alternatives:

ufak (colloquial “small”): Bu ufak hata önemsiz.
Diminutives: küçücük, ufacık (“tiny”): Bu küçücük hata…

Any quick pronunciation tips for this sentence?

ü in küçük: front rounded vowel (like German ü or French u).
ö in önemsiz: front rounded vowel (like German ö).
ç = “ch” as in “chair.”
Stress is typically on the last syllable: ku‑ÇÜK, ö‑nem‑SİZ, ha‑TA.