Emphatic and focus particles

Compare Došao je Marko (Marko came) with Došao je čak i Marko (Even Marko came). The facts are the same; what changed is the speaker's attitude — surprise. Serbian carries a great deal of this attitude in a handful of short words: čak, baš, bar/barem, tek, i and samo/jedino. Grammarians call them focus particles: each one points at a single word or phrase and tells the listener how to feel about it.

Two rules that hold for all of them

1. The particle stands right before the word it emphasises. Move it and you emphasise something else: Samo Ana pije kafu (only Ana, nobody else) is not Ana pije samo kafu (only coffee, nothing else).
2. The particle never changes anything. It has one form, and the word after it keeps exactly the case and form it would have without it: Vidim Marka → Vidim čak i Marka; u Beogradu → baš u Beogradu.

What each particle adds

čak, čak i, čak ni

Čak marks something as surprising, beyond what you would expect. Before a noun or pronoun it is usually followed by i: Čak i moj otac je plakao — Even my father cried. In a negative sentence the i becomes ni: Čak ni on nije znao — Not even he knew. Before a number or an amount, čak alone means 'as much as, a whole': Čekali smo čak tri sata — We waited a whole three hours.

baš

Baš has two jobs. Before a noun, pronoun or adverb it means 'exactly, precisely, of all things': Baš danas mi se pokvario auto — Today of all days my car broke down. Before an adjective or adverb it is an intensifier, 'really': To je baš lepo — That's really nice. With a negative it softens: nije baš = 'not exactly, not really'.

bar and barem

Bar and barem mean the same thing, 'at least'; barem is a little fuller and more emphatic. They name the minimum the speaker will settle for: Pozovi me bar sutra — At least call me tomorrow. Barem nije padala kiša — At least it wasn't raining.

tek

Tek says something happened later, or there is less, than expected. With a time it is English 'not until' — and note that Serbian keeps the verb positive: Došao je tek u deset = He didn't come until ten. With an amount it means 'only, merely': Ima tek dvadeset godina — She is only twenty. With a verb in the past it means 'only just': Tek sam stigao — I've only just arrived.

Do not add ne after tek. English says 'he didn't come until ten', but Serbian says Došao je tek u deset — positive verb, tek before the time.

i meaning 'even'

You know i as 'and'. Placed directly before a single stressed word — not joining two things — it means 'even' or 'too': To zna i dete — Even a child knows that. I ja bih to uradio — I would have done it too. Čak i is simply the stronger version.

samo and jedino

Samo means 'only, just' and limits whatever follows: Hteo sam samo da pitam — I only wanted to ask. Jedino is stronger, 'the only one, nothing but': Jedino me to brine — That's the only thing that worries me.

Placement is the meaning. Put the particle directly in front of the word you want to highlight, and do not change that word's ending: Vidim samo Marka, never samo Marko when Marko is the object.