Secondary Imperfectivization Chains

By B1 you know that Czech verbs come in aspect pairs and that prefixes make perfectives: psát (imperfective "write") → napsat (perfective "write down, get written"). What that tidy picture hides is a second, deeper layer of derivation. When a prefix does more than just perfectivize — when it adds a new lexical meaning — the language is left with a perfective verb that has no imperfective partner. So Czech re-builds one by suffixation: přepsat ("rewrite," perfective) spawns přepisovat ("be rewriting," imperfective). This process, secondary imperfectivization, is the engine that keeps hundreds of prefixed verbs in proper aspect pairs. Mastering it is what lets you predict a verb's partner instead of memorizing each one. This is a reference page; read it slowly.

Why the second layer has to exist

Prefixation in Czech does two jobs at once. It almost always perfectivizes, and it very often changes the meaning. Most of the time those two jobs are inseparable. Consider the imperfective root psát ("to write"):

• na-
  • psát → napsat — perfective, meaning still basically "write (and finish)." Here the prefix is roughly empty: it just perfectivizes. So psát / napsat is a clean pair, no second layer needed.
• pře-
  • psát → přepsat — perfective, but now meaning "rewrite, write over." The prefix added meaning. There is no plain imperfective verb that means "rewrite" — psát means only "write."

That gap is the problem. "I am rewriting it" is an ongoing, imperfective situation, but the only "rewrite" verb in stock is the perfective přepsat. Czech fills the gap morphologically: it takes the prefixed perfective and re-imperfectivizes it with a suffix, yielding přepisovat. Now "rewrite" has a full pair: přepisovat (imperfective) / přepsat (perfective).

Walking one root through the full chain

Let's follow the psát root all the way, because seeing every link makes the mechanism click. Each prefix produces a perfective with a distinct meaning, and each of those gets its own secondary imperfective in -isovat (from the -pis- stem alternant).

The pattern is mechanical: the perfective ends in -psat, the secondary imperfective swaps it for -pisovat. Each pair sits at the same lexical meaning; only the aspect differs.

The first two show the secondary imperfective doing exactly what it was built for: describing the new prefixed meaning as an ongoing process. The perfective partners (podepsat, zapsat, přepsat) would view those same actions as single completed events.

The secondary-imperfective suffixes

Several suffixes do this work, and which one a verb takes is partly predictable from its stem and partly lexical. The four productive ones:

A defining feature is that secondary imperfectivization often lengthens or alters the root vowel, and that vowel change is itself a signal of the process:

• koupit (pf) → kupovat (impf): the diphthong ou shortens to u.
• dát (pf) → dávat (impf): á stays long but the stem is enlarged with -va-.
• zavřít (pf) → zavírat (impf): ř
  • í reshapes to ír.
• začít (pf) → začínat (impf): the nasal-derived -čít becomes -čínat.

Both sentences are habitual — repeated, ongoing — which is precisely the territory of the imperfective. The perfective koupit / dát could not carry "every morning" or "always."

Aspect triplets: when there are three layers

Some roots stack to three layers, producing a genuine aspect triplet: a base imperfective, a derived perfective, and on top of that an iterative/frequentative form built by adding -va- again.

The third layer (dávávat, also chodívat from chodit, bývat from být) is the iterative/frequentative — a habit so repeated it gets its own form, usually with a nostalgic "used to, time and again" flavour. For its own treatment, see iterative and frequentative verbs.

Predicting the partner — the payoff for English speakers

English has no morphology like this, so the instinct is to learn each Czech verb pair as an unrelated lexical fact. The reward of understanding secondary imperfectivization is that you stop memorizing and start deriving. Given a prefixed perfective, you can often build or recognize its imperfective:

• See podepsat ("sign," pf)? Its partner is podepisovat.
• See vybrat ("choose, withdraw," pf)? Its partner is vybírat.
• See otevřít ("open," pf)? Its partner is otvírat / otevírat.

And in reverse, an imperfective in -ovat/-ávat/-írat with a meaningful prefix tells you the perfective is the suffix-stripped form. This is the same machinery described from the building-blocks side in forming imperfectives with suffixes and forming perfectives with prefixes; here we have simply followed the two operations as a chain. The contrast between empty and meaning-adding prefixes — the trigger for whether a second layer is needed at all — is treated in empty vs meaning-adding prefixes.

That is the derived imperfective podepisovat in a habitual sentence — the canonical place a secondary imperfective earns its keep, because no perfective can express a recurring habit.

Common Mistakes

The perfective podepsat forms its future synthetically (podepíšu). To get an analytic budu-future you would need the secondary imperfective: budu podepisovat ("I'll be signing"), used when the signing is drawn out or repeated.

"Every day" forces a habitual reading, which only the secondary imperfective přepisovat delivers. The perfective přepíšu would mean a single, completed rewrite.

A durative adverb like dlouho ("for a long time") wants the imperfective zapisoval. The perfective zapsal views the noting-down as a single finished act, which clashes with extended duration.

The secondary imperfective of koupit is kupovat (present kupuju), with the diphthong ou shortened to u. Keeping the ou (koupuju) is a non-word.

Key Takeaways

• A meaning-adding prefix both changes the sense and perfectivizes; to express that new sense imperfectively, Czech re-derives an imperfective by suffix.
• The secondary-imperfective suffixes are -ovat, -ávat, -ívat, -vat, usually with a root-vowel change (koupit → kupovat, dát → dávat, zavřít → zavírat).
• Typical chain: base imperfective → prefixed perfective (new meaning) → secondary imperfective; some roots add a third iterative layer (dát → dávat → dávávat).
• To recover a partner, strip the secondary suffix from a prefixed -ovat/-ávat/-írat verb to get the perfective, or add it to get the imperfective.
• This is how Czech maintains aspect pairs for hundreds of prefixed verbs — and why predicting partners beats memorizing them.