Croatian makes a distinction between three genders (masculine, feminine, and neuter), seven cases (nominative, genitive, dative, accusative, vocative, locative, instrumental) and two numbers (singular and plural).
The three genders correspond, to a certain extent, with the word ending, so most nouns with -a are feminine, -o and -e neuter, and the rest mostly masculine but with some feminine.
zub - tooth (masculine)
kuća - house (feminine)
oko - eye (neuter)
The grammatical gender of a noun affects the morphology of other parts of speech (adjectives, pronouns, and verbs) attached to it.
There are no articles in the Croatian language.
Just as with nouns, adjectives change their forms according to the three grammatical categories of gender (masculine, feminine, neuter), number (singular or plural) and case (nominative, genitive, dative, accusative, vocative, locative, instrumental).
Adjectives describing a noun have to agree with it in gender, case, and number.
lijep prozor - a beautiful window (masculine, singular, nominative)
lijepim slikama - to beautiful pictures (feminine, plural, dative)
lijepo more - beautiful sea (neuter, singular, accusative)
Although there are no articles in Croatian, there are “indefinite adjectives”, which receive special endings when describing indefinite nouns. However, these are not commonly used in everyday communication.
Ovo je nov auto. Novi auto je crven. - This is a new car. The new car is red.
Adverbs in Croatian are immutable, meaning they do not inflect and do not change their form. Adverbs are used to determine the time, place, manner, cause, point and the amount of the action of the verb.
Some examples of Croatian adverbs are: jučer (yesterday), ovdje (here), vrlo (very), uvijek (always).
In the Croatian language, there are personal (ja, ti), possessive (moj, tvoj), reflexive (sebe, se), demonstrative (ovaj, taj), interrogative (tko, što), relative (kakav, kolik), and indefinite (netko, gdjetko) pronouns.
Personal pronouns inflect according to the same seven cases as nouns.
Croatian allows deletion of the subject pronoun.
Bojim se. - I am afraid.
In the Croatian language, verbs have five grammatical categories: tense, person, voice, mood, and aspect.
The indicative has seven tenses: present, past, futures I and II, pluperfect, aorist and imperfect. The latter two are not used often in daily speech.
Besides the indicative, Croatian uses the imperative, conditional, and the optative. Optative is in its form identical to the perfect participle. It is used by speakers to express a strong wish.
Verbal aspect is distinguished in English by using the simple or progressive (continuous) forms. 'He washed the dishes' indicates that the action was finished; 'He was washing the dishes' indicates that the action was ongoing (progressive). Croatian, like all Slavic languages, has the aspect built into the verbs, rather than expressing it with different tenses.
Croatian uses one for completed actions (perfective aspect) and another for iterative and progressive (imperfective aspect). The downside is that there’s no specific rule on how to form the perfective verb. In some cases, you simply add a prefix to the imperfective verb, but there are several prefixes to choose from and not all can be used with every verb.
Kuhao sam ručak. - I was cooking lunch (imperfective).
Skuhao sam ručak. - I had cooked lunch (perfective).
Aspect is the most challenging part of Serbo-Croatian grammar. Although aspect exists in all other Slavic languages, learners of Serbo-Croatian who already know even one of several other Slavic languages may never learn to use aspect correctly.
Croatian has a rich case structure that is reflected in the declension of nouns and adjectives. That allows for a great deal of freedom in word order.
In English, for example, the word order shows a difference in meaning between "Man bites dog" and "Dog bites man". In Croatian, Čovjek grize psa (Man bites dog) and Čovjeka grize pas (Dog bites man) have the same word order, but the meanings are shown by the noun endings.
Any order of the three constituents is grammatically correct, and the meaning is clear because of the declensions. However, the usual order is subject–verb–object, as, for instance, in English.
In Croatian, each preposition has an assigned case. If an inflectable word follows a preposition, the word is declined in the same case as the preposition's assigned case.
For instance, prepositions od, ispred, van must be followed by the genitive case; prema, nasuprot - by the dative; kroz, niz - by the accusative; na, po - by the locative; pred, za - by the instrumental.
This is a very brief overview of Croatian grammar. To truly master it, you will need to study each of the parts of speech in much more detail. However, this overview will hopefully give you a general idea of the Croatian grammatical system and introduce you to the main points you should consider when learning.