Learn Hardcore Turkish: Arkadaşım gelmedi, onsuz da sinemaya gidiyoruz. - My friend didn’t come, we are going to the cinema without him.

onsuz = o (he/she/it) + the suffix -sUz “without,” with the buffer consonant -n-: o + n + suz → onsuz.
The suffix changes by vowel harmony: -sız/-siz/-suz/-süz. Here, the last vowel of o is back/rounded, so we get -suz.
Other pronouns: bensiz (without me), sensiz (without you), bizsiz (without us), sizsiz (without you plural/polite), onlarsız (without them).

What is da doing in onsuz da?

This da/de is the enclitic meaning “also/too/even,” and here it adds the nuance “even/anyway”: onsuz da ≈ “even without him/her.”
It underscores that you will still go despite the friend’s absence.
It is written separately (as its own word) and is not the locative case ending.

Is this da the same as the locative case -da/-de?

No. Two different things:

Enclitic da/de (“also/too/even”): a separate word, never becomes ta/te, chosen by vowel harmony (back vowel → da, front vowel → de). Example: Ben de geliyorum.
Locative case -da/-de/-ta/-te (“at/in/on”): a suffix stuck to the noun, and it can be ta/te after a voiceless consonant. Examples: evde (in the house), parkta (in the park).

Why is it sinemaya and not just “sinema + -e”?

Because sinema ends in a vowel. When adding the dative -(y)e/-(y)a, Turkish inserts a buffer y: sinema + (y)a → sinemaya.
More examples: okul + a → okula (no buffer, ends with consonant); oda + a → odaya (buffer y appears).

Why is the verb gidiyoruz (present continuous) used for a future plan?

Turkish often uses the present continuous -iyor for near-future, arranged, or decided plans, similar to English “We’re going (later).”

gideceğiz (future) is also possible, but feels more neutral/predictive.
gidiyoruz suggests the plan is set or imminent; with onsuz da it carries a clear “we’re going anyway” vibe.

Can I say gideceğiz instead of gidiyoruz here?

Yes: … onsuz da sinemaya gideceğiz is correct.
Nuance:

gidiyoruz = arranged/definite plan, often near future or “we’re (still) going.”
gideceğiz = “we will go” (more neutral prediction or decision).

Is it okay to mix past (gelmedi) and present continuous (gidiyoruz) like this?

Yes. gelmedi (simple past: “didn’t come”) reports a completed event; gidiyoruz describes the current/near-future plan. This kind of tense mix is natural and common in Turkish.

Why is there no subject pronoun biz?

Turkish verb endings encode the subject. gidiyoruz already shows 1st person plural (-uz), so biz is optional. Use biz only for emphasis/contrast: Biz onsuz da gidiyoruz (“We (as opposed to others) are going, too.”).

Could da here mean “but”?

Not in this position. When da is the enclitic after onsuz, it means “also/even.”

To express “but/however,” use conjunctions like ama, fakat, yine de, buna rağmen:
- Arkadaşım gelmedi ama/yine de sinemaya gidiyoruz.

Can I move da to other words, and how does that change the meaning?

Yes, da/de attaches to the word it emphasizes:

Onsuz da sinemaya gidiyoruz = “We’re going even without him/her.”
Sinemaya da gidiyoruz = “We’re going to the cinema too (in addition to somewhere else or another activity).”
Biz de sinemaya gidiyoruz = “We’re going too (like others).” Each placement changes what is being marked as “also/even.”

Are there other ways to say “without him/her” here?

O olmadan: “without him/her (lit. without him/her being).”
Example: O olmadan da sinemaya gidiyoruz.
O gelmese de …: “even if he/she doesn’t come …” (hypothetical/conditional).
Onun yokluğunda: “in his/her absence” (more formal).

Is the word order fixed?

Flexible, with emphasis changes:

Neutral: Onsuz da sinemaya gidiyoruz.
Emphasize destination: Sinemaya, onsuz da gidiyoruz.
End-focus on destination: Onsuz da gidiyoruz sinemaya. All are grammatical; choice depends on what you want to stress.

Why is it gidiyoruz and not “gitiyoruz”? What happened to the t?

With the progressive -iyor, the verb gitmek shows a stem alternation: git- → gid- before a vowel, so you get gidiyorum/gidiyoruz. This is a common pattern with a small set of verbs (compare etmek → ediyor).

Can you give a quick morphology breakdown of the whole sentence?

Arkadaş-ım = friend + my (possessive 1sg)
gel-me-di = come + negation -me + simple past -di → “did not come”
on-suz = o (3sg) + -sUz “without” (with buffer n: o + n + suz → onsuz)
da = enclitic “also/even”
sinema-ya = cinema + dative -(y)a “to the cinema”
git-iyor-uz = go + progressive -iyor + 1pl -uz → “we are going”