Learn Hardcore Turkish: Patatesleri doğrar mısın? Soğanı da ince ince kesmeni istiyorum. - Can you chop the potatoes? I want you to slice the onion finely.

In Turkish, the aorist + question particle (V‑r mi?) is a common, polite way to make a request. Doğrar mısın? therefore functions like “Would/Could you chop…?” The present continuous question (doğruyor musun?) asks about an action happening right now (“Are you chopping…?”) and is not a request. Alternatives for requests include doğrayabilir misin? (“can you chop?”) and the more formal/plural doğrar mısınız?

Why is it patatesleri and not patatesler or just patates?

patatesleri = patates + ler + i (plural + definite accusative): “the potatoes” as a specific set; it’s the direct object of the verb and is marked as definite.
patatesler (no -i) would be the subject or a generic plural but not a definite object.
patates (no plural, no -i) would mean “some potato(s)” in an indefinite sense.
Turkish marks definiteness on direct objects with -ı/-i/-u/-ü; if the object is indefinite, you omit the accusative.

What does da in Soğanı da do, and how is it written?

da/de is the clitic meaning “also/too.” It attaches to the word it emphasizes and is written separately: soğanı da = “the onion too.” It obeys vowel harmony (da after back vowels, de after front vowels) and, unlike the locative suffix -da/-de, it never becomes -ta/-te and is never written with an apostrophe.

What does the repetition ince ince mean?

Reduplication of adjectives/adverbs intensifies or specifies manner. ince ince means “very thinly/in thin slices,” stronger or more specific than a single ince. Other common pairs: yavaş yavaş (slowly, bit by bit), teker teker (one by one), küçük küçük (into tiny pieces).

How does Soğanı da ince ince kesmeni istiyorum hang together grammatically?

The clause soğanı da ince ince kesmeni is a nominalized complement to istiyorum (“I want”). Structure:

kes-me-n-i = verb stem kes-
- nominalizer -me
  - 2nd person possessive -n (“your”) + accusative -i (marks the whole clause as the object of “want”).
The embedded clause has its own object soğan-ı (“the onion”) and adverb ince ince. Overall: “I want your cutting (thinly) of the onion.”

Why kesmeni and not kesmeyi or kesmek with istiyorum?

kesmeni istiyorum = “I want you to cut (it).” The embedded subject is “you,” shown by -n.
kesmeyi istiyorum or more commonly kesmek istiyorum = “I want to cut (it).” The subject is “I.” With istemek, -mek is the most neutral choice; -meyi is possible but more nominal/marked.

Can I say doğramanı instead of kesmeni? What’s the nuance between kesmek and doğramak?

Yes: Soğanı da ince ince doğramanı istiyorum is fine. Nuance:

kesmek = to cut (general; often implies slicing).
doğramak = to chop/dice. For onions, ince ince doğramak usually implies finely chopping; ince ince kesmek leans toward thin slicing (e.g., rings).

Where does the -n- in kesmeni come from? Do I need to say senin too?

The -n- is the 2nd person possessive marker, showing the subject of the embedded action is “you”: kes-me-n = “your cutting.” You can optionally add the genitive subject: Senin soğanı da ince ince kesmeni istiyorum, but it’s usually omitted when context is clear.

Is it natural to mix a request (doğrar mısın?) with a statement of desire (… istiyorum)?

Yes. Speakers commonly switch between request strategies, even in the same exchange. The aorist question sounds like a polite ask; … istiyorum can sound a touch firmer (closer to “I’d like you to…”). You could also make both requests parallel: Soğanı da ince ince keser misin?

Can I move da or change the word order?

Soğanı da ince ince kesmeni istiyorum (default; “the onion too”).
Soğanı ince ince de kesmeni istiyorum shifts “also” to the manner (“also thinly”), which changes the meaning.
Soğanı da kesmeni ince ince istiyorum is ungrammatical; adverbs like ince ince normally sit right before the verb they modify.
In questions, object-before-verb is standard: Patatesleri doğrar mısın? Putting the object after the verb (Doğrar mısın patatesleri?) sounds marked/colloquial.

How do I pronounce the ğ and the dotless ı here?

ğ (yumuşak g) doesn’t create a new consonant; it lengthens or glides the preceding vowel: doğrar ≈ doo-rar, soğanı ≈ soo-an-ı.
ı is a high back unrounded vowel (IPA [ɯ]); mısın ≈ mɯ-sɯn.

Any spelling gotchas with mı/mi and spacing?

The question particle is written separately and follows vowel harmony: doğrar mısın?, gelir misin?, yapar mısınız? Never write it fused (doğrarmısın is wrong).
The clitic da/de (“also”) is also written separately: soğanı da. Don’t confuse it with the locative suffix -da/-de, which attaches to the noun.