The comitative is Finnish's most ornamental case. It means "accompanied by," and it is unlike any case English has a category for: it is always plural in form, it always carries a possessive suffix, and it belongs almost entirely to formal and literary registers. In everyday life you would say the same thing with the postposition kanssa. But the comitative appears in news, ceremony, and elevated prose often enough that a serious learner must be able to read it — so this page is about recognition first, production second.
The shape: stem + -ine- + possessive
The comitative marker is -ine-, and it is never the whole word. Two things attach to it obligatorily:
- it sits on the plural stem (the -i- is fused into -ine-), so the form always looks plural; and
- it must be followed by a possessive suffix agreeing with the sentence's subject.
So "with his/her children" is built laps- + -ine- + -en → lapsineen. There is no *lapsine and no singular comitative at all.
Naapuri lähti lomalle lapsineen.
The neighbour went on holiday with the/their children. (formal)
Presidentti saapui puolisoineen.
The president arrived with his/her spouse. (formal)
Look hard at puolisoineen: the president has one spouse, yet the form is plural (puoliso-ine-en). The comitative's plural shape does not mean "several." It is simply the only shape the case has. This is the single most confusing thing about it for English speakers, so hold onto it: plural form, singular or plural meaning.
The possessive suffix must match the subject
Because the possessive suffix is obligatory, it also has to point at the right person. This is where learners who have half-learned lapsineen go wrong: -een is third person ("his/her/their"). If you came with your children, you need first-person -ni.
| Subject | Comitative of lapsi | Meaning |
|---|---|---|
| minä | lapsineni | with my children |
| sinä | lapsinesi | with your children |
| hän | lapsineen | with his/her children |
| me | lapsinemme | with our children |
| te | lapsinenne | with your (pl) children |
| he | lapsineen | with their children |
Tulin kokoukseen kaikkine papereineni.
I came to the meeting with all my papers.
Muutimme maalle koirinemme ja kissoinemme.
We moved to the countryside with our dogs and cats.
Adjectives take -ine- too — but not the possessive
When a noun in the comitative has a modifier, the modifier also inflects in -ine- and agrees. The possessive suffix, however, rides only on the head noun at the end of the phrase — the adjective carries the -ine- alone.
Hän lähti kaikkine tavaroineen.
He left with all his belongings.
Johtaja esitteli suunnitelman suurine lupauksineen.
The director presented the plan with its grand promises. (literary)
In kaikkine tavaroineen, the modifier kaikki becomes kaikkine (-ine-, no possessive) and the noun tavara becomes tavaroineen (-ine- + possessive). Splitting the possessive off onto the adjective — *kaikkineen tavaroineen — is wrong.
A note on harmony
One mercy: the -ine- element never harmonises. It is always e/i, whatever the vowels of the stem. Compare a back-vowel word and a front-vowel word:
Vieraat saapuivat lahjoineen.
The guests arrived with their gifts.
Hän myi talon kaikkine huonekaluineen.
He sold the house with all its furniture.
Lahja (back) → lahjoineen; huonekalu → huonekaluineen — both in -ine-, no -inä- variant exists. The possessive suffixes that follow — -ni, -si, -en, -mme, -nne — are all harmony-neutral too, so a well-formed comitative never makes you pick a front-vowel form at all.
What you should actually say: kanssa
For all its elegance, the comitative is not what a Finn reaches for when arranging to meet a friend. The everyday "with" is the postposition kanssa + genitive, and that is what you should produce in speech.
Menen elokuviin ystävän kanssa.
I'm going to the movies with a friend. (everyday)
Hän tuli juhliin vaimonsa kanssa.
He came to the party with his wife. (everyday)
Compare the registers directly: the news anchor says Presidentti saapui puolisoineen; you say Tulin vaimon kanssa. Both are correct; they live in different worlds. Reach for the comitative when you are writing formally or want a compact, elevated flourish — and reach for kanssa the rest of the time.
Common Mistakes
❌ Hän saapui perheine.
Incorrect — the comitative must end in a possessive suffix: perheineen.
✅ Hän saapui perheineen.
He arrived with his family.
❌ Tulin kokoukseen papereineen.
Incorrect — with a 1st-person subject the suffix must be -ni, not 3rd-person -en.
✅ Tulin kokoukseen papereineni.
I came to the meeting with my papers.
❌ Hän myi talon kaikilla huonekaluineen.
Incorrect — the modifier also takes -ine-, not the adessive: kaikkine.
✅ Hän myi talon kaikkine huonekaluineen.
He sold the house with all its furniture.
❌ Hän lähti vaimoineen kanssa.
Incorrect — never combine the comitative with kanssa; each means 'with' by itself.
✅ Hän lähti vaimoineen.
He left with his wife. (or, everyday: vaimonsa kanssa)
❌ Hän tuli lapset kanssa.
Incorrect — the everyday alternative kanssa takes the genitive: lasten.
✅ Hän tuli lasten kanssa.
He came with the children.
Key Takeaways
- The comitative -ine- means "accompanied by," is always plural in form, and always carries a possessive suffix — there is no singular and no bare form.
- The possessive suffix must match the subject: lapsineni (my), lapsinesi (your), lapsineen (his/her/their).
- A modifier also inflects in -ine- but leaves the possessive to the head noun: kaikkine tavaroineen.
- The -ine- element never harmonises (always e/i); only the final possessive suffix does.
- It is (formal)/(literary). In speech use kanssa + genitive (vaimon kanssa) — and never stack the two.
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- Abessive -tta/-ttä: 'without'B1 — The abessive -tta/-ttä means 'without' (rahatta, syyttä), but modern Finnish prefers ilman + partitive; the living form is the 3rd-infinitive -matta.
- Instructive -n: 'by means of / in a manner'C1 — The instructive plural -n survives in frozen phrases — jalan, käsin, omin silmin, paljain jaloin — meaning 'by means of' or 'in a way'; it is not productive.
- kanssa: 'with' and the ComitativeA2 — kanssa is the everyday 'with' of company — genitive noun plus kanssa, or a pronoun with a possessive suffix (minun kanssani) — and it is not the 'with' of instruments.
- Possessive Suffixes: -ni, -si, -nsaA2 — Six suffixes mark the owner directly on the noun — taloni, talosi, talonsa, talomme, talonne, talonsa — the obligatory Finnish way to say 'my, your, his' house.