There are more verb forms to learn: another participle, another form of verb "to be", and another future tense. Yes, they are all used in real life.
What is this?! This is a word that coresponds to English "-ing" forms. It's really constructed easily. One just adds -ći to the 3rd pers. pl. of the present tense of impf. verbs:
pišem (pišu) "write" → pišući "writing"
padam (padaju) "fall" → padajući "falling"
pečem (peku) "bake" → pekući "baking"
idem (idu) "go" → idući "going"
tečem (teku) "flow" → tekući "flowing"
It's a participle, so it's something between an adjective, an adverb, and a verbal form. It can be used in various ways. First, all pres. part. can be used freely in sentences as adverbs, meaning "while x-ing":
Idući ulicom, ugledao säm nju. "While walking the street, I spotted her"
Zaspao säm gledajući televiziju. "I fell asleep while I was watching TV."
The case of nouns appended to the participle is the same used with the verb:
idem ulicom (ins.) → idući ulicom
gledam televiziju (acc.) → gledajući televiziju
Another use is indicating a manner, how you did something, but it's really again the same thing, you were doing something at the same time:
Vozili smo se pjëvajući. lit. "We were driving singing." = "We sang while driving."
Učim prepisujući iz knjige. lit. "I'm learning copying from the book." = "I'm learning by copying from the book."
The third use is as a real adjective. Not all pres. participles allow that. Moreover, some of them developed special meanings when used as an adjective:
idući "following, next"
budući (from budem) "future" , as in "future tense"
Vidjëla je leteće tanjure. "She saw flying saucers."
However, their most often use is in fixed phrases, like leteći tanjuri or tekući sapun "liquid soap", since it can be phrased using relative clauses:
tekuća voda "flowing water" (opp. to "still") = voda koja teče
leteći kukci "flying insects" = kukci koji lete
Word idući means "following" or "next" but the more frequent one is sljëdeći which means only "next", and it's the main way to express that meaning in Croatian. If used as an adverb (not as an adjective) it's spelled slightly differently: slijëdeći.
The opposite meaning, "previous", is expressed by prošäo, prošla, simply the past participle of prođem, used as an adjective:
Prošle godine smo išli u Francusku. "Last year we went to France."
Sljëdeće godine idemo u Italiju. "Next year we go to Italy."
Both time phrases are in genitive singular.
Another Future Tense
The verb budem, - is very curious one: it's the only verb that has only forms for present, no past, and no infinitive. It's a kind of perf. counterpart of säm, bio — "to be".
It means something like "start being", "get to be", "become" (and German "werden"). For instance:
Ako budem gladan... "If I get hungry..."
It's meaning and aspect, in a way, imply future events. Therefore, it's used to make another form of future tense — with the same past participle used for the past tense:
Spavao säm. "I was sleeping."
Budem spavao. "I'll be sleeping."
In some parts of Croatia (we will discuss dialects later) this is the only form of future tense.
This verb is completely regular, but lacks all forms but the present tense.
So this tense comes cheap: the past participle you already know, and there's just a peculiar verb with present only and all forms of it regular. It could have been much worse.
Now, we have two future tenses, which one should we use and when? Answer: in Standard Croatian, you use budem-future only in conditional clauses, and it's optional. In Colloquial Croatian, you can mix them as you want.
Budem is not a clitic — it can go to any position in the sentence, but it normally precedes a past participle. Questions can be formed with and without li, and it alters the meaning:
Budeš li išla... = ako budeš išla
Budeš išla..? = hoćeš li ići...?
Since hoću has two meanings: "want" and "auxiliary verb to create future", sentences with hoću imply intentions, but sentences with budem imply certain future events. Just ću is neutral, it's a pure auxiliary, but it normally not used in questions.
You might think about short-cutting, using säm for the past, budem for the future tense, but you still need infinitives to produce forms like trëbam spavati "I need to sleep".
That much about the "exact future tense".
More Verbal Nouns
While there's a verbal noun (gerund) on -'je (e.g. čitanje "reading", kuhanje "cooking", učenje "learning") for most verbs, some verbs have other verbal nouns as well.
Some unprefixed impf. i-verbs can add -nja to their past stem to make a verbal (action) noun which feels less connected to the verb and process and more feels like a "thing". Commonly used such nouns are:
gradim "build" → gradnja "building"
krećem, kretao "move" → kretnja "movement"
patim "suffer" → patnja "suffering"
prijëtim "threaten" → prijëtnja "threat"
radim "work, do" → radnja "plot (e.g in book)"
slutim "foresee" → slutnja "premonition"
šećem, šetao "walk" → šetnja "walk"
štedim "save (money)" → štednja "savings"
Such words are quite often used, e.g. gradnja is used in names of countless Croatian construction companies. If the past root ends on an s or z, it's converted to an š or ž:
mrzim "hate" → mržnja "hate"
nosim "carry" → nošnja "(folk) costume"
pazim "watch, take care" → pažnja "attention"
vozim "drive" → vožnja "drive"
Some prefixed i- and n-verbs (impf. and perf.) can add -äk to their present stem:
boravim "spend time, dwell" → borav-äk "residing"
ispravim "correct" (perf.) → isprav-äk "correction"
odlazim "leave" → odlaz-äk "leaving"
postupim "carry out" (perf.) → postup-äk "procedure"
pritisnem "press" (perf.) → pritis-äk "pressure"
umetnem "insert" (perf.) → umet-äk "insertion, filler"
Some perf. verbs of other types can add -täk to their past part. f after discarding -la:
počnem, počeo "begin" (perf.) → poče-täk "begin"
zadam "give a task" (perf.) → zada-täk "task"
Sometimes -etäk is added to an perf. i-verb or n-verb:
završim "complete" (perf.) → završ-etäk "correction"
Updated 2014-04-27. moved