Perfective to Imperfective
Adding a prefix to a verb usually makes it perfective (a single, completed action). To describe that exact same action happening repeatedly or continuously, you can "stretch" the perfective verb back into an imperfective one by adding the suffix -ivati or -avati.
Verbs Ending in "-ivati"
Many perfective verbs are made iterative by adding -ivati. In the present tense, the -iva- drops out and they take the endings -ujem, -uješ, -uje, -ujemo, -ujete, -uju.
For example, zapisati (to write down) is perfective. To talk about regularly writing things down, we use the iterative zapisivati.
This pattern applies to many verbs to indicate recurring habits or ongoing situations.
Spelling Changes
When forming these iterative verbs, the root sometimes undergoes slight spelling changes. For instance, the ije in ocijeniti (to evaluate) shortens to je in its iterative form ocjenjivati.
Similarly, root consonants can soften. The d in nagraditi (to reward) becomes a đ in the iterative nagrađivati.
Verbs Ending in "-avati"
Other verbs take the suffix -avati to form their iterative aspect. Unlike the -ivati group, verbs ending in -avati keep the a in the present tense, taking the standard endings -avam, -avaš, -ava, -avamo, -avate, -avaju.
