Instrumental of Feminine Consonant Nouns

Level 3Sounds Like instrumental ženskih imenica na suglasnik

Feminine nouns ending in a consonant (such as ноћ, љубав, радост) have two possible singular instrumental endings: -ју and -и. The ending -ју triggers sound changes like jotation and epenthesis, and is strongly preferred when the noun stands on its own. The ending -и is typical when accompanied by an attribute or a preposition.

How It Works

Most feminine consonant nouns (feminine consonant nouns) form their instrumental singular using two endings: -и and -ју.

1. The ending -и
This ending attaches directly to the consonant base without sound changes:

  • ноћ → ноћи
  • љубав → љубави
  • болест → болести
  • ствар → ствари

Because -и matches the genitive, dative, vocative, and locative singular, using -и alone in a prepositionless (bare) instrumental can cause ambiguity. Therefore, the ending -и is typically used when an accompanying adjective or demonstrative pronoun clearly marks the instrumental case (e.g., с великом љубави, том ствари), or after governing prepositions (such as са / с, међу, or под). When the noun is used without a preposition (bare instrumental), the form in -ју (e.g., љубављу, болешћу) is strongly preferred to distinguish it clearly from the genitive, dative, and locative singular.

Note on nouns ending in -о: Nouns such as со (genitive соли) or мисао (genitive мисли) stem from historical -л (сол, мисл). Despite ending in -о in the nominative, they are feminine i-stems belonging to this declension class, not neuter nouns.

Note on nouns taking only -и: While most feminine consonant nouns accept both endings, a handful of specific nouns—such as раж (rye), зоб (oats), and коб (fate)—only take the ending -и (ражи, зоби, коби) and never permit forms in -ју in standard Serbian.

2. The ending -ју (triggers Jotation, Epenthesis, and Place Assimilation)
Adding -ју triggers sound changes at the end of the stem:

  • Epenthetic -л- with labials (п, б, в, м): љубав + -ју → љубављу; крв + -ју → крвљу
  • Dental consonants (т, д): смрт + -ју → смрћу (т + ј → ћ); памет + -ју → памећу; глад + -ју → глађу (д + ј → ђ)
  • Sonorants (л, н): со (stem сол-) + -ју → сољу (л + ј → љ); јесен + -ју → јесењу (н + ј → њ)
  • Consonant clusters (Jotation + Place Assimilation): Jotation turns т into ћ and л into љ. Subsequently, place assimilation (једначење сугласника по месту творбе) shifts the preceding dental с into postalveolar ш: ст + -ју → -шћу (радост → радошћу; кост → кошћу); сл + -ју → -шљу (мисао, stem мисл- → мишљу)
  • Absorption after alveolopalatals (ћ, ђ): The /j/ is absorbed: ноћ + -ју → ноћу; помоћ + -ју → помоћу; жеђ + -ју → жеђу
  • Retention after postalveolars and palatals (ч, ж, ш) and the alveolar vibrant (р): The suffix -ју remains intact without further jotation: реч + -ју → речју; and with р: ствар + -ју → стварју

3. Irregular Consonant Stems
Two feminine kinship nouns with consonant bases follow unique patterns: мати (stem матер-) takes the ending -ом (матером), while кћи (stem кћер-) uses either кћери or кћерју.

4. Syntactic Usage and Fixed Expressions
Prepositionless nouns standing alone without modifiers strongly favor -ју (кошћу, крвљу, глађу) to mark the instrumental clearly. Moreover, several forms in -ју have lexicalized as common adverbs or prepositions, such as ноћу ('at night') and помоћу ('by means of').

Examples (4)

  1. Прихватио је награду с великим узбуђењем и радошћу.

    He accepted the award with great excitement and joy.

    Word by Word: Accepted he-is award with great excitement and joy.

    Радошћу shows jotation of the cluster ст into шћ when combined with the instrumental ending -ју.

  2. Гледао ју је с неизмерном љубављу.

    He looked at her with boundless love.

    Word by Word: Looked her is with boundless love.

    Љубављу features the epenthetic consonant -л- inserted between the labial stem ending -в and the suffix -ју.

  3. Борио се против болести том последњом снагом и моћи.

    He fought the illness with that last bit of strength and power.

    Word by Word: Fought self against illness that last strength and power.

    Because the noun is modified by demonstrative and adjective attributes ('том последњом'), the ending -и is natural and unambiguous.

  4. Отворио је тајанствени сандук помоћу старог кључа.

    He opened the mysterious chest by means of an old key.

    Word by Word: Opened is mysterious chest by-means-of old key.

    Помоћу is the instrumental singular of помоћ, functioning here as a preposition meaning 'by means of'.

Common Mistakes

  • Using the masculine instrumental ending -ом on feminine consonant nouns

    Путовали смо целом ноћом кроз планине.
    Путовали смо целом ноћу кроз планине.

    Even though they end in a consonant, these nouns belong to the feminine gender and never take masculine endings like -ом or -ем.

  • Forgetting the epenthetic -л- or jotation when adding -ју

    Гледао ју је са великом љубавју.
    Гледао ју је са великом љубављу.

    Labial consonants (п, б, в, м) require the insertion of an epenthetic -л- before -ју, giving љубављу rather than љубавју.

  • Using the ending -и when the noun stands entirely alone

    Урадио је то љубави према породици.
    Урадио је то љубављу према породици.

    Without an adjective or preposition to indicate the instrumental, the form љубави is heard as a genitive or dative. An isolated noun requires љубављу.

How It Connects

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Instrumental of Feminine Consonant NounsLevel 3

Learn This First

To correctly form and use the instrumental of feminine consonant nouns (like ноћу or љубављу/љубави), learners first need to recognize feminine nouns ending in a consonant and understand the functions of the instrumental case.