Plural Instrumental

The plural instrumental (инструментал множине) handles multiple items or people across several key functions:

1. Endings and Morphological Rules
In modern Serbian, Dative, Locative, and Instrumental plurals share identical endings:

• Class II nouns (ending in -а in nominative singular): Take -ама without sibilarization (velars к, г, х stay unchanged: књига → књигама, never *књизама).
  књига → књигама, девојка → девојкама, комшија (m.) → комшијама.
• All other regular nouns: Take -има.
  Neuter: село → селима, поље → пољима.
  Feminine in a consonant: ствар → стварима, ноћ → ноћима.
  Polysyllabic masculine: студент → студентима.
  Many monosyllabic masculine nouns take the extended plural infix -ов- / -ев- (град → градовима, муж → мужевима). However, a distinct group of common monosyllabic masculine nouns uses the short plural directly with -има without any infix (e.g., дан → данима, зуб → зубима, прст → прстима, гост → гостима).
  Note on sound changes: Sibilarization before -има occurs in short plurals when a stem ends in a velar (к, г, х → ц, з, с): ученик → ученицима, орах → орасима, предлог → предлозима. While many monosyllabic masculine stems ending in velars take the extended infix -ов- (вук → вуковима, круг → круговима, страх → страховима) and thus avoid sibilarization, notable monosyllabic nouns take short plurals with sibilarization, such as ђак → ђацима, or have common short plural doublets such as знак → знацима and звук → звуцима.
  Irregular Plurals vs. Collective Nouns:
  • Regular or suppletive irregular plurals take the standard plural ending -има: људи (people, from човек) → људима (са људима), око (eye) → очи → очима, and уво / ухо (ear) → уши → ушима.
  • In contrast, collective plurals like деца (children) and браћа (brothers) behave grammatically as feminine singulars in form, taking the singular ending -ом rather than -има (са децом, са браћом).
• Adjectives and Determiners: Take -им (or optionally extended -има) across all genders: новим, добрим, овим.
• Plural Personal Pronouns: Personal pronouns also use identical forms for Dative, Locative, and Instrumental: ми → нама (with us: са нама), ви → вама (with you: са вама), они / оне / она → њима (with them: са њима).

2. Meaning: Company, Instruments, and Prepositions
• Accompaniment (with people or things): Always requires са / с.
When to use са vs. с: The longer form са is required before words starting with sibilants and affricates (с, з, ш, ж, ц, ч, џ, ђ, ћ), before consonant clusters ending in a sibilant (e.g., са псима), and before non-syllabic or monosyllabic pronouns (са мном, са њим, and optionally са нама / са њима). Everywhere else, both с and са are used, with с being standard before other sounds: с пријатељима or са пријатељима.
Шетам са пријатељима. (I am walking with friends.)
Идемо у биоскоп са њима. (We are going to the cinema with them.)
• Spatial relationships: Common prepositions like међу (among / between), над (above), под (under), and пред (in front of) take the plural instrumental to indicate location.
Седели смо међу пријатељима. (We sat among friends.)
• Means and Tools: Never use a preposition. Use plural when referring to naturally paired items or tools distributed among individuals:
Једемо штапићима. (We eat with chopsticks.)
Деца пишу оловкама. (The children are writing with pencils.)
Сликамо четкицама. (We paint with brushes.)
Note on transit: Modes of transport normally stay in the singular instrumental in Serbian, even with plural subjects (Путујемо возом / аутобусом / авионом, not *возовима).

3. Time and Repetition
When used without a preposition, the plural instrumental conveys either duration or habitual repetition:

• Duration over multiple units: сатима (for hours), годинама (for years), месецима (for months).
  Чекали смо сатима. (We waited for hours.)
• Recurring / habitual time: викендима (on weekends), ноћима (at night / night after night), јутрима (in the mornings).
  Викендима шетам поред реке. (On weekends I walk along the river.)