Learn Hardcore Croatian: Ne volim usisavati navečer, jer je usisavač bučan. - I don’t like to vacuum in the evening because the vacuum cleaner is noisy.

In Croatian, when one verb follows certain verbs like voljeti (to like/love), htjeti (to want), morati (must/have to), trebati (need to), etc., the second verb is normally in the infinitive.

So:

Ne volim usisavati. – I don’t like to vacuum / vacuuming.
Volim čitati. – I like to read / reading.
Moram raditi. – I have to work.

English often uses a -ing form (I don’t like vacuuming), but Croatian uses the infinitive (usisavati).

What is the difference between "usisavati" and "usisati"?

Both come from usisati (to vacuum / to suck in), but they differ in aspect:

usisavati – imperfective: focuses on the process or habit
- Ne volim usisavati. – I don’t like vacuuming (in general / as an activity).
usisati – perfective: focuses on the completed action
- Neću usisati danas. – I won’t vacuum (even once / get it done) today.

In this sentence, the speaker is talking about liking the activity in general, so the imperfective form usisavati is the natural choice.

What exactly does "navečer" mean, and how is it different from "večer"?

večer = evening (a noun)
- Ova večer je lijepa. – This evening is nice.
navečer = in the evening / at night (in the evenings) (an adverbial time expression)
- Ne volim usisavati navečer. – I don’t like vacuuming in the evening.

You can think of navečer as a fixed adverb meaning in the evening, typically for when you do something at that time.

Where can "navečer" go in the sentence? Is the order fixed?

The meaning stays the same, but word order can vary slightly for style or emphasis. All of these are possible:

Ne volim usisavati navečer, jer je usisavač bučan. (very natural, neutral)
Navečer ne volim usisavati, jer je usisavač bučan. (slight emphasis on in the evening)
Ne volim navečer usisavati, jer je usisavač bučan. (also fine, slightly less common)

Croatian word order is relatively flexible, but the version in your sentence is the most typical.

Why is there a comma before "jer"?

Jer means because and introduces a subordinate clause giving a reason:

Ne volim usisavati navečer, jer je usisavač bučan.
– I don’t like vacuuming in the evening, because the vacuum cleaner is loud.

In standard Croatian punctuation, a comma is normally required before "jer" when it joins two clauses:

Ne idem van, jer sam umoran. – I’m not going out, because I’m tired.
Kasnim, jer je bila gužva. – I’m late, because there was traffic.

Why is it "jer je usisavač bučan" and not just "jer usisavač bučan"?

Croatian needs a form of “to be” (biti) in the present tense in sentences like this.

je is the 3rd person singular of biti = is
- On je bučan. – He is loud.
- Usisavač je bučan. – The vacuum cleaner is loud.

So the clause must be:

jer je usisavač bučan – because the vacuum cleaner is loud.

Leaving out je (jer usisavač bučan) would be ungrammatical in standard Croatian.

What gender and case is "usisavač", and why does "bučan" look like that?

usisavač (vacuum cleaner) is:

masculine, singular
here in the nominative case (it’s the subject of the clause)

The adjective bučan (loud, noisy) must agree with the noun in gender, number, and case:

usisavač – masculine, singular, nominative
→ bučan – masculine, singular, nominative

Other forms, for comparison:

bučna – feminine singular nominative
bučno – neuter singular nominative
bučni – masculine plural nominative

Examples:

Auto je bučan. – The car is loud. (m.sg.)
Glazba je bučna. – The music is loud. (f.sg.)
More je bučno. – The sea is noisy. (n.sg.)

I don’t see the word “I” in the Croatian sentence. Where is it?

Croatian is a pro‑drop language: subject pronouns (ja, ti, on, ona…) are often omitted because the verb ending already shows who the subject is.

Volim usisavati. – I like vacuuming.
Ne volim usisavati. – I don’t like vacuuming.

The form volim clearly indicates 1st person singular (I), so ja is optional:

Ja ne volim usisavati navečer. – I don’t like vacuuming in the evening. (with emphasis on I)
Ne volim usisavati navečer. – Same meaning, more neutral.

Could I say this with "sviđa mi se" instead of "volim"? What’s the difference?

You can use sviđati se (to be pleasing to someone), but the structure changes:

Ne sviđa mi se usisavati navečer.
– Literally: Vacuuming in the evening does not please me.

Difference:

voljeti: closer to to like / to love; more direct and common with activities
- Ne volim usisavati navečer. – I don’t like vacuuming in the evening.
sviđati se: more like to be pleasing to someone
- Used a lot for opinions about things/people:
  - Ne sviđa mi se ovaj film. – I don’t like this movie.

For activities/habits, voljeti + infinitive (volim usisavati) is usually the most natural.

Are there other natural ways to say “I don’t like vacuuming in the evening” in Croatian?

Yes, some common variations:

Ne volim usisavati navečer, jer je usisavač bučan.
– The original; very natural.
Navečer ne volim usisavati, jer je usisavač bučan.
– Slight emphasis on in the evening.
Ne volim navečer usisavati, jer je usisavač bučan.
– Same meaning, just a different word order.
With a noun form instead of an infinitive:
- Ne volim usisavanje navečer, jer je usisavač bučan.
  – Literally: I don’t like vacuuming (as a noun) in the evening.
  – Grammatically fine, but less common than using the infinitive here.

All of these are understandable, but the sentence you started with is the most typical and idiomatic.