There are two ways of spelling the auxiliary verb in the future tense. First, it can precede the main verb in which case it is always spelled separately, for example:
Ja ĉu raditi 'I will work'
It can also be spelled after the main verb, in which case the following rules apply:
Doĉi ĉu 'I will come'
| Croatian & Bosnian Muslim | Serbian |
| delete -i, spell separately, e.g. radit ĉu 'I will work.' | delete
-ti, spell together, e.g., radiĉu |