требати

A common challenge in advanced Serbian is navigating the division between standard normative grammar and colloquial usage regarding требати.

1. Modal Usage (Impersonal Auxiliary)
In standard Serbian, when требати expresses deontic necessity, recommendation, or obligation, it is almost exclusively impersonal (безлично). It typically has no nominative subject of its own and remains fixed in the 3rd person singular neuter:
• Present: треба
• Perfect (Past): требало је / није требало
• Future I: требаће
• Conditional: требало би

Modal требати licenses two types of verb complements:
• Direct infinitive: Standardly used for general, impersonal statements, questions, or instructions:
– Треба знати правила. ('One should know the rules.')
– Шта треба радити? ('What should be done?')
– Требало би поћи на време. ('One ought to leave on time.')
• да + презент: Predominantly used when a specific agent performs the action. The embedded verb agrees with the agent while треба stays invariable:
– Ми треба да кренемо. (Ми controls кренемо, while треба remains fixed in the 3rd singular neuter).

2. Lexical Usage (Personal Agreement and Partitive Genitive)
When требати means 'to be needed or required', its agreement patterns depend on the grammatical role of the required item:
• Nominative subject: It conjugates across person, number, and tense to agree with the subject, while the experiencer takes the dative case (треба ми; потребан ми је):
– Овај речник ми не треба. (3rd sg. agreeing with речник)
– Нису нам требали ти проблеми. (3rd pl. masc. participle agreeing with проблеми)
• Partitive genitive: When the needed entity is an unspecified quantity, substance, or mass noun in the genitive case, требати remains impersonal in the 3rd person singular neuter:
– Треба ми новца за пут. ('I need some money for the trip.')
– Требало нам је више времена. ('We needed more time.')

3. Register Distinctions, Regional Norms, and Exceptions
• Colloquial speech vs. Standard Serbian: In casual speech, native speakers frequently conjugate modal требати personally (*ја требам да идем*, *требали смо доћи*). In standard Serbian, this personal modal use is generally treated as non-standard.
• Relative clause exception: Standard normative authorities (such as Ivan Klajn and Predrag Piper in Нормативна граматика српског језика) recognize an established syntactic exception in relative clauses introduced by који with plural antecedents in compound tenses. Here, personal agreement is tolerated or even preferred to avoid an awkward grammatical clash: Дошли су сви они који су требали да дођу (alongside impersonal који је требало да дођу).
• Cross-regional standards (Croatian): Standard Croatian prescribes personal inflection of modal trebati when followed by an infinitive (e.g., trebam ići). In standard Serbian, the impersonal construction remains the baseline rule.
• Analogy with морати: Because морати ('must') is fully personal (ја морам, ти мораш), learners frequently transfer personal endings to modal требати by false analogy. Outside of specific relative clause structures, keep modal требати impersonal in standard Serbian contexts.