Learn Hardcore Turkish: Öğretmen sunumu kısa tutmamı istediğini belirtti; ben de çıktıları kısalttım. - The teacher stated that she wanted me to keep the presentation short; so I shortened the printouts.

Because it’s a specific/definite direct object of the verb in the embedded clause. In Turkish, definite objects take the accusative. In the phrase sunumu kısa tutmam, the thing being kept short is a particular presentation, so sunum gets -u.

What exactly does tutmamı mean, and how is it built?

It’s a nominalized verb meaning “my keeping.” Breakdown:

tut- = keep/hold
-ma = verbal noun suffix (turns the verb into “keeping”)
-m = 1st person singular possessive (“my”)
-ı = accusative marker (because this whole chunk is the object of another verb) So tut-ma-m-ı = “my keeping (it).”

Where is the word “me” in “wanted me to keep …”? Should there be benim?

The “me” is encoded by the 1st person possessive on the nominalized verb (tut-ma-m = “my keeping”). You can explicitly add the genitive subject:

Benim sunumu kısa tutmamı… Including benim is optional when the subject is clear from context; dropping it is very common.

What is istediğini doing here? Why not just istedi?

İstediğini is a nominalized clause meaning “what he/she wanted,” and it serves as the object of belirtti.

iste- = want
-dik/-diğ- = nominalizer/participial suffix
-i = 3rd person possessor (“his/her wanting”)
-ni = accusative (object of belirtti) So istediğini = “that (s/he) wanted (it).” Using bare istedi would change the structure to “(s/he) wanted …,” rather than “(s/he) stated that (s/he) wanted ….”

Why use belirtti instead of söyledi? Are both okay?

Both are grammatical. Belirtmek is “to state/indicate” and sounds a bit more formal or precise. Söylemek is “to say” and is more neutral. You could say:

Öğretmen … istediğini söyledi (more neutral)
Öğretmen … istediğini belirtti (more formal/pointed)

Could I skip the nominalization and say “Öğretmen sunumu kısa tutmamı istedi, …”?

Yes, that’s also correct and a bit simpler: Öğretmen sunumu kısa tutmamı istedi, ben de … The original sentence emphasizes the act of stating (reporting) the desire (belirtti), while this version directly reports the wanting (istedi).

Can I use ki here, like “Öğretmen belirtti ki …”?

You can: Öğretmen belirtti ki sunumu kısa tutmamı istiyordu/istiyor. Using ki is acceptable (and common in formal writing), but Turkish often prefers the -dik/-diğ- nominalization (istediğini belirtti) for embedded statements. Both are fine; the nominalized version feels more compact and native-like in many contexts.

What does ben de mean here? Is it “I too” or “so I”?

It’s the additive particle de/da with ben, giving a natural “so I (for my part)” or “I too” sense. It often signals a responsive action: the teacher said X; I (accordingly) did Y. Important:

ben de (separate) = “I too/as well”
bende (one word) = “on me/with me” (a different meaning)

Why is çıktı-lar-ı in the accusative and plural?

-lar marks plural: “printouts/outputs.”
-ı is the accusative, showing a definite/specific set: “the printouts.” If you meant some unspecified printouts, you could say bazı çıktıları (“some of the printouts,” still accusative because specific subset) or drop specificity in another way (e.g., birkaç çıktı kısalttım—no accusative on an indefinite object).

Does çıktı mean “printouts” or “outputs”?

Both, depending on context:

Office/classroom context: çıktı = “printout(s)/handout(s)”
Computing/data context: çıktı = “output(s)” Here, given presentations, “printouts/handouts” is the likely reading.

What’s the difference between kısa tutmak and kısaltmak?

kısa tutmak = “to keep (something) short” (maintain brevity, often as a guideline or target length).
kısaltmak = “to shorten” (actively make it shorter than it was). So the teacher’s request is phrased as a guideline (kısa tutmamı), while your action is a concrete shortening (kısalttım).

Would it be more consistent to say I shortened the presentation (not the printouts)?

If you literally shortened the presentation, yes: Ben de sunumu kısalttım or Ben de sunumu kısa tuttum (the latter implies you kept it brief, not necessarily that you cut it down). The given sentence instead says you shortened the printouts (çıktıları), which is fine if that’s what actually happened.