A student of mine once ordered kafa sa mlijeko every morning for a month before anyone corrected her. The waiter always understood; that's not the point. The word she wanted was mlijekom — the instrumental case — and it's honestly the friendliest of the seven. It does two jobs: the tool you do something with, and the company you do it in. Learn one ending and one small rule about s/sa, and it's yours.
Published 9 June 2026
I'm Maja, I teach Montenegrin, and I can tell you the instrumental is the case my students stop fearing first. Not because it's rare — you'll use it in your first café order — but because its logic is so clean.
When a noun is the instrument — the thing you do the action by means of — you put it in the instrumental and you use no preposition at all. Where English says "with a pen" or "by bus", we just change the ending:
This is the part English speakers resist. Your instinct screams that "with" must be there. It mustn't. The ending is the "with".
When you do something together with someone (or something), that's company, and company takes the preposition s or sa plus the instrumental:
The whole case in one line: tool = no preposition, company = s/sa. If English "with" means "using", drop the s. Pišem olovkom, never pišem s olovkom — unless you and the pencil are somehow writing as colleagues.
And s versus sa? Same word. We say sa when the next word starts with s, z, š or ž (sa školom, sa zetom) or would be hard to say otherwise (sa mnom — with me). Elsewhere, plain s. If you default to sa everywhere while you learn, no one in Podgorica will bat an eyelid.
Singular, the ones you'll actually use:
Notice something? Three of those four patterns are just -om. This case mostly rhymes.
One bonus you get free: a family of verbs takes the instrumental with no preposition, and the most useful is baviti se — to do/be into something. Bavim se jogom (I do yoga), bavi se ribolovom (he's into fishing). Learn that one verb and you can talk about hobbies all evening.
Cover the answers: write with a pen (perom) · by car (autom) · with my brother (s bratom) · tea with honey (čaj sa medom) · with me (sa mnom). Got four? You've got the case.
If you're collecting the set: the locative tells you where things are, and the genitive — the busiest of the seven — handles "of" and "from". The instrumental is the one I'd teach second, right after the accusative, precisely because coffee orders depend on it.
So — s kim (with whom) are you having your next coffee, and what will you stir it with? Say both out loud in Montenegrin. If you'd like the endings drilled into reflex with real sentences and a patient fox, that's exactly what Gora is for.