Infinitive + ћу / ћу + Infinitive

In Serbian, the future tense (футур I) combines the short forms of the auxiliary verb хтети (ћу, ћеш, ће, ћемо, ћете, ће) with the lexical infinitive. Because these auxiliary forms are unaccented enclitics (енклитике), they cannot stand at the very beginning of a clause.

This creates two fundamental word-order and orthographic scenarios:

1. An element precedes the verb:
When a subject pronoun (личне заменице), noun, or adverbial begins the sentence, the enclitic occupies the second structural slot. The full, unshortened infinitive appears later in the clause as an independent word—it does not need to follow the clitic immediately, as other clitics or adverbs can intervene:
• Ја ћу читати (I will read)
• Ми ћемо сигурно доћи (We will certainly come)
• Сутра ћу му је дати (Tomorrow I will give it to him)

Note on standard spoken Serbian: When an overt subject or initial element is present, standard Serbian very frequently uses да + present instead of the infinitive (e.g., Ја ћу да читам, Сутра ћу да радим). Both are standard, but the да construction is especially common in everyday speech.

2. The verb begins the clause:
Because Serbian freely omits unstressed subject pronouns (изостављање личне заменице), the verb often opens the clause to host the auxiliary clitic. When inverted like this, the да construction cannot be used; you must use the infinitive base. What happens next depends on the infinitive ending:
• Verbs in -ти: The ending -ти drops entirely, and the auxiliary attaches directly to the stem as a single fused word:
  - чита-ти + ћу → читаћу
  - ради-ти + ћемо → радићемо
  - Stems ending in -с: Under consonant assimilation of place, stem-final с turns into ш before ћ (e.g., јести → јешћу; плести → плешћу).
• Verbs in -ћи: Verbs ending in -ћи (such as доћи, ићи, рећи, моћи) never fuse in writing. The complete infinitive is retained and written as a separate word:
  - доћи + ћу → доћи ћу
  - рећи + ће → рећи ће

Important notes:
• Pronunciation: Even though доћи ћу is written as two words, it is pronounced smoothly as a single rhythmic unit, exactly like читаћу.
• Standard Serbian vs. Croatian: In standard Croatian, -ти verbs drop only the -i and stay detached (čitat ću). In standard Serbian, dropping -ти entirely and fusing the stem with the clitic into one word (читаћу) is the mandatory orthographic rule.
• Negation: The negative future (негација у футуру I) uses stressed negative forms (нећу, нећеш...). Since they carry stress, they can start a clause and are always written as separate words before the full infinitive (Нећу читати / Нећу да читам, never *не читаћу).