This is the error that costs you meaning, not just polish. Swedish has a possessive that English simply lacks: the reflexive possessive sin / sitt / sina, which means "his/her/its/their own" and points back to the subject of the clause. Because English has no such word — "his" covers both "his own" and "someone else's his" — learners default to hans / hennes / deras for everything. The problem is that in Swedish those two choices are not interchangeable: they refer to different people. Saying hans when you mean sin doesn't sound slightly off — it tells your listener you mean a different person. This page drills the contrast through the errors that actually change who did what.
The core rule, then the cardinal error
When the possessor is the subject of the clause, use the reflexive sin / sitt / sina. When the possessor is anyone else, use hans / hennes / dess / deras.
- Han älskar *sin fru. = He loves *his own wife.
- Han älskar *hans fru. = He loves *his (some other man's) wife.
Both are grammatical Swedish sentences. They just mean different things. That is why this is a meaning error, not a grammar slip.
❌ Han älskar hans fru.
Incorrect (if you mean his OWN wife) — 'hans' forces a reading of some other man's wife.
✅ Han älskar sin fru.
He loves his own wife — reflexive 'sin' points back to the subject 'han'.
❌ Han tvättade hans bil.
Incorrect (if you mean his own car) — this unambiguously says he washed SOMEONE ELSE'S car.
✅ Han tvättade sin bil.
He washed his own car — 'sin' = belonging to the subject.
Why English speakers fall into it
English has no dedicated reflexive possessive. To force the "own" reading, English bolts on the word own — his own car — but the bare possessive his is ambiguous and English speakers live happily with that ambiguity. Swedish refuses the ambiguity: it gives you two separate words and makes you choose. So the transfer error is structural — there is no English form to map sin onto, so the learner reaches for hans/hennes, the only possessive they know, and unknowingly picks the "someone else's" reading every time. The fix is to treat sin as the translation of "his/her/their OWN" and to ask, on every third-person possessive, "does this belong to the subject?"
sin agrees with the thing owned, not the owner
Before the next error, one mechanic that surprises English speakers: sin/sitt/sina agrees with the possessed noun's gender and number, not the owner's sex. So "his" and "her" both become sin before a common-gender noun — the word carries no information about whether the subject is male or female.
| Possessed noun | Reflexive form | Example |
|---|---|---|
| common (en) singular | sin | sin bil, sin fru, sin mamma |
| neuter (ett) singular | sitt | sitt hus, sitt jobb, sitt barn |
| plural | sina | sina barn, sina vänner, sina böcker |
Hon hämtade sitt barn och packade sina väskor.
She picked up her (own) child and packed her (own) bags. sitt (neuter barn), sina (plural väskor) — agreement is with the thing owned.
The plural error: deras → sina
The reflexive isn't only for "his/her." A plural subject doing something to its own thing needs sina, not deras. Deras is the non-reflexive plural possessive — "their" pointing at other people.
❌ De målade deras hus i somras.
Incorrect (if it's their own house) — 'deras' points at another group's house.
✅ De målade sina hus i somras.
They painted their (own) houses last summer — reflexive 'sina' refers back to 'de'.
❌ Föräldrarna älskar deras barn.
Incorrect (if they mean their own children) — 'deras' makes it some other parents' children.
✅ Föräldrarna älskar sina barn.
The parents love their (own) children.
Why: the subject-versus-other logic is identical in the plural; only the form changes. Subject owns it → sina. Someone else owns it → deras. The same test that picks sin over hans picks sina over deras.
The subject-constraint trap: sin can NEVER be the subject
Here is the error that goes the other way — overusing sin. The reflexive must point back to a subject, which means it can never be (or be inside) the subject itself. A subject has nothing earlier in its own clause to refer to. So when the possessive sits on the subject, you must use hans/hennes/deras, even when it means "his own."
❌ Sin bil är fin.
Incorrect — 'sin' cannot appear in the subject; there is no preceding subject for it to refer back to.
✅ Hans bil är fin.
His car is nice — the possessor is in the subject, so use 'hans'.
❌ Sina barn bor utomlands.
Incorrect — the possessive is part of the subject, so the reflexive is impossible here.
✅ Hennes barn bor utomlands.
Her children live abroad — subject possessive must be hennes.
Why: sin is a pointer, and a pointer needs a target that comes earlier in the clause. The subject is the first thing in the clause — there is nothing before it to anchor to. This catches learners who, having finally learned to love sin, start using it everywhere including the subject. The rule: sin lives in the object / complement zone (after the verb), looking back at the subject. It is structurally barred from the subject slot. A clause like Hon tog sin väska works because sin (in the object) looks back to hon (the subject); flip it to subject position and it collapses.
Anna sålde sin lägenhet, men hennes lägenhet var redan slutsåld i annonsen.
Anna sold her (own) flat, but her flat was already marked sold in the ad. 'sin' in the object refers to Anna; 'hennes' starts a new clause where the flat is the subject.
A clean side-by-side
| Sentence | Means |
|---|---|
| Erik körde sin bil. | Erik drove his own car. |
| Erik körde hans bil. | Erik drove another man's car. |
| De bjöd in sina grannar. | They invited their own neighbours. |
| De bjöd in deras grannar. | They invited another group's neighbours. |
Han lånade sin brors bil, inte hans grannes.
He borrowed his (own) brother's car, not his neighbour's. 'sin' = the subject's brother; 'hans' would point elsewhere.
Common Mistakes
❌ Han borstar hans tänder.
Incorrect — for 'his own teeth' you need the reflexive; 'hans' implies someone else's.
✅ Han borstar sina tänder.
He brushes his (own) teeth — plural possessed noun → sina.
❌ Hon glömde hennes nycklar.
Incorrect — 'hennes' here means another woman's keys.
✅ Hon glömde sina nycklar.
She forgot her (own) keys.
❌ De sålde deras hus. (meaning their own)
Incorrect — subject-owned plural needs sina, not deras.
✅ De sålde sitt hus.
They sold their (own) house — neuter 'hus' → sitt.
❌ Sin lägenhet är liten.
Incorrect — 'sin' is barred from the subject; nothing precedes it to refer to.
✅ Hennes lägenhet är liten.
Her flat is small.
❌ Barnen leker med deras leksaker. (their own)
Incorrect — if the toys belong to the children (the subject), use sina.
✅ Barnen leker med sina leksaker.
The children are playing with their (own) toys.
Key Takeaways
- sin / sitt / sina = "his/her/its/their own," and it must point back to the subject of its clause.
- hans / hennes / deras refer to someone else — using them for "his/her/their own" is a meaning error: Han tvättade hans bil says he washed another man's car.
- sin agrees with the possessed noun (common → sin, neuter → sitt, plural → sina), never with the owner's sex.
- The reflexive can never sit in the subject — a subject has nothing earlier to refer to, so a subject possessive is always hans/hennes/deras (Hans bil är fin, never sin bil är fin).
- English has no reflexive possessive, which is exactly why English speakers default to hans/hennes — retrain yourself to ask "does this belong to the subject?" on every third-person possessive.
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- sin/sitt/sina vs hans/hennes/derasB1 — The decision procedure for Swedish's reflexive possessive. Use sin/sitt/sina ('one's own') when the owner is the third-person SUBJECT of the SAME clause; use hans/hennes/deras for everyone and everything else. 'Han tvättar sin bil' means he washes his OWN car; 'Han tvättar hans bil' means he washes some other man's car — a distinction English can't make in a single word. The hard part is embedded clauses, where 'sin' points to the nearest subject.
- The Reflexive Possessive sin/sitt/sinaB1 — sin/sitt/sina means 'his/her/its/their own' and points back to the subject of the same clause: Han älskar sin fru = his OWN wife, while Han älskar hans fru = some other man's wife. It agrees with the thing owned (like min/mitt/mina), is strictly 3rd-person and subject-bound — and, the detail competitors skip, can NEVER itself be part of the subject.
- The Reflexive Pronoun sigA2 — When the object of a verb is the same person as the subject, Swedish 1st and 2nd persons just reuse the ordinary object pronoun (jag tvättar mig, du tvättar dig) — but the 3rd person has a dedicated reflexive word, sig, for he/she/it/they/one. Using honom or henne instead of sig flips the meaning to 'someone else', a mistake English's '-self' suffix makes very easy to fall into.
- Possessive DeterminersA1 — The words for 'my/your/his...' before a noun: min/mitt/mina, din/ditt/dina, vår/vårt/våra and sin/sitt/sina AGREE with the possessed noun's gender and number, while hans, hennes, dess, er and deras are INVARIABLE. The rule English habits keep breaking: a noun after any possessive goes BARE (min bil, never *min bilen) — no definite suffix, no front article.