Now, let's learn the genitive case in plural! Unfortunately, it's not a simple form to create. For start, nouns get the following endings:
|nouns in -a (≈ fem.)||-a → -a* (or -i)|
|neuter nouns (≈ in -o, -e)||-o, -e → -a*|
|masc. nouns not in -a||N-pl -i → -a*|
|fem. not in -a (e.g. noć)||add -i|
Goran se boji mrava. Goran is afraid of ants.
There's no difference in spelling of genitive plural and singular, therefore the sentence could also mean Goran is afraid of an ant.
In the beginning, I wrote that I will disregard vowel length, i.e. differences between long and short vowels, since many people in Croatia don't have that difference in their speech. However, those that keep the difference, and Standard Croatian, have the -a in G-pl always long – while -a in other case endings is always short – so forms mrava (G) and mrava (G-pl) are not really pronounced the same. That specific length in G-pl is sometimes indicated in writing by putting a circumflex sign over the long vowel: mravâ. It's by no means mandatory, you will see it from time to time. (A recent Croatian orthography manual recommends using a macron – a line over vowel – instead, e.g. mravā; it's still very rare.)
There are no twists for nouns ending in -a, -o or -e preceded by only one consonant: nouns just get -a in G-pl.
Other nouns can get a kind of 'lengthening' (I indicated it by an asterisk).
How does it work? If a neuter or feminine noun would have two consecutive consonants just before the genitive plural -a, an additional a gets inserted between those consonants:
pjesma song →
sestra sister → sestara
društvo society →
pismo letter → pisama
Some nouns (e.g. sestra sister, listed above), move the stress to the inserted -a-.
This insertion never happens if those last two consonants are either st, št, šć, zd, žd or žđ (so-called non-splittable sequences):
zv||mjesto place → mjesta|
Masculine nouns that get short plural endings, get the -a always attached to their nominative form, even if they have a specific case-base:
kolač cake →
magarac (magarc-) donkey → magaraca
pas (ps-) dog → pasa
pisac (pisc-) writer → pisaca
This makes their G-pl form distinct from the singular genitive. For example:
Ana se bojala pasa. Ana was afraid of dogs.
Ana se bojala psa. Ana was afraid of the dog.
Few masculine nouns that end in two consonants which are not a non-splittable sequence, get an additional a in the same way as feminine and neuter nouns:
bicikl bicycle →
koncert concert → koncerata
dokument document → dokumenata
Some nouns on -a preceded by two or more consonants can have both -a in gen. plural (with an additional a inserted) and -i. Both are used, but versions with -i prevail in everyday speech, at least in larger cities in Croatia:
daska plank →
dasaka / daski
karta card, map → karata / karti
olovka pen → olovaka / olovki
školjka shell → školjaka / školjki
voćka fruit tree → voćaka / voćki
These nouns can have both -a and -i but they never get an additional a inserted; they mostly end in -nja; the ending -i is more common in spoken language:
pažnja care, attention
The following often used nouns have just -i in G-pl:
bajka fairy tale|
plahta bed sheet ®
torba bag, big purse
žalba complaint, appeal
The noun čovjek man/human has the irregular plural ljudi people; its G-pl is also just ljudi.
The noun sat – when meaning hour – has G-pl sati.
Some nouns get an -u or something similar, instead of the endings listed above. These three nouns get always -u:
|noga leg||ruka arm||sluga m servant|
These nouns get -iju:
gost guest →
kost f bone → kostiju
The strange plurals of oko eye and uho ear get -iju as well:
|oči f pl. eyes → očiju||uši f pl. ears → ušiju|
The following noun can have both -a and -iju:
prst finger/toe →
prsta / prstiju
nokat (nokt-) fingernail, toenail → nokata / noktiju
vrata n. pl. door → vrata / vratiju
Additionally, the following colloquial noun can get both -i and -iju, but the latter ending is seen as very colloquial:
dečko (dečk-) m boy → dečki / dečkiju ®
All such unexpected forms in the G-pl are listed in the Core Dictionary.
Compared to all the twists I had to explain for nouns, the genitive plural forms of adjectives are as simple as possible:
The adjective-often-used-as-pronoun svi has an alternative, non-standard form that's sometimes seen is G-pl: sviju, besides the expected svih.
We can review endings of adjectives in DL, G and I cases in both singular and plural:
® Besides plahta, words čaršav or čaršaf are often used in Bosnia and completely prevail in Serbia, in meaning thin sheets, while plahta is used for thick covers.
The noun dečko is less common outside Croatia, and it's not even used in some Croatian regions; it's most common in Zagreb and surrounding areas.