Learn Hardcore Croatian: Volim učiti hrvatski s tobom. - I like to study Croatian with you.

Volim clearly shows 1st person singular (I like).
Ja volim učiti hrvatski s tobom is grammatically correct, but it sounds emphatic, like:
- I like learning Croatian with you (implying maybe others don’t).

So:

Neutral, most common: Volim učiti hrvatski s tobom.
Emphatic: Ja volim učiti hrvatski s tobom.

What is the infinitive form of volim, and how is it conjugated?

Volim comes from the verb voljeti (to like, to love).

Present tense (singular + plural):

ja volim – I like / I love
ti voliš – you like / you love (singular, informal)
on/ona/ono voli – he/she/it likes / loves
mi volimo – we like / love
vi volite – you like / love (plural or formal)
oni/one/ona vole – they like / love

In this sentence, volim = I like / I love. Context usually decides whether it feels more like like or love in English; here it’s closer to I like learning Croatian with you.

Why is učiti in the infinitive? Could it also be učim?

Here učiti is the infinitive (to learn), used after volim:

Volim učiti. – I like to learn / I like learning.

You cannot say Volim učim. That’s ungrammatical.

Compare:

Volim učiti hrvatski. – I like learning Croatian.
Učim hrvatski. – I am learning Croatian / I study Croatian.

So:

After volim, you use the infinitive: učiti, not učim.

What aspect is učiti here, and what’s the difference between učiti and naučiti?

Učiti is imperfective, meaning an ongoing or repeated action: to be learning, to learn in general.

Naučiti is perfective, meaning to finish learning something, to master it.

Volim učiti hrvatski. – I like learning Croatian (the process).
Volim naučiti nove riječi. – I like it when I’ve learned new words / I like to learn new words (more result-focused).

In your sentence, you’re talking about the activity of learning Croatian, so the imperfective učiti is correct.

Why is it hrvatski and not hrvatski jezik?

Literally, hrvatski jezik means Croatian language.

Very often, Croatian speakers drop the word jezik and use only the adjective hrvatski, which then functions like a noun:

učiti hrvatski (jezik) – to learn Croatian (language)
pričati hrvatski – to speak Croatian
pisati hrvatski – to write (in) Croatian

So hrvatski here is the accusative singular masculine form of the adjective, used alone to mean Croatian (language). The full, more formal version would be:

Volim učiti hrvatski jezik s tobom.

What case is hrvatski in, and why?

Hrvatski is in the accusative singular masculine form.

Reason: it is the direct object of the verb učiti (to learn).
You learn what? – hrvatski.

Pattern:

nominative: hrvatski jezik – Croatian language (subject)
accusative: Učim hrvatski (jezik). – I am learning Croatian (language).

Why is it s tobom and not just tobom?

The preposition s means with. The pronoun tobom (you, in the instrumental case) by itself just means by you/with you in form, but in normal speech you must include the preposition:

s tobom – with you

In Croatian, the preposition is required to express with:

Idem s tobom. – I’m going with you.
Volim učiti s tobom. – I like learning with you.

So tobom is the instrumental form of ti, and it must be used with s (or sa) to mean with you.

What’s the difference between s tobom and sa tobom?

Both are correct and mean with you.

s tobom – shorter form, very common.
sa tobom – slightly longer variant, used especially:
- to avoid awkward sound combinations, or
- for stylistic/phonetic reasons.

Here, s tobom is smooth and completely natural. Sa tobom is also fine, just a bit more emphatic or careful in pronunciation. You can safely use s tobom in this sentence.

Why is the form tobom used, and not ti or tebe?

Croatian pronouns change form depending on the case (their grammatical role):

For ti (you, singular informal):

Nominative (subject): ti – Ti učiš hrvatski. (You are learning Croatian.)
Accusative/Genitive: tebe/te – Volim te. (I love you.)
Dative/Locative: tebi – Govorim tebi. (I’m talking to you.)
Instrumental: tobom – Učim s tobom. (I learn with you.)

The preposition s (with) requires the instrumental case, so the correct form is tobom:

s tobom – with you

Could the word order be different, like S tobom volim učiti hrvatski?

Yes. Croatian word order is quite flexible. All of these are grammatically correct:

Volim učiti hrvatski s tobom. – neutral.
Volim s tobom učiti hrvatski. – slight emphasis on with you as part of the activity.
S tobom volim učiti hrvatski. – stronger emphasis on with you (as in: With you, I like learning Croatian).
Hrvatski volim učiti s tobom. – emphasizes Croatian.

The basic, neutral-sounding version is the one you have:
Volim učiti hrvatski s tobom.

Is there any difference between Volim učiti hrvatski s tobom and Rado učim hrvatski s tobom?

Yes, there’s a subtle difference:

Volim učiti hrvatski s tobom. – Literally: I like/love to learn Croatian with you. Focus on liking the activity.
Rado učim hrvatski s tobom. – Literally: I gladly learn Croatian with you. It means you are willing and happy to do it; it sounds a bit more about your attitude or readiness.

Both are positive, natural sentences.
Volim učiti… is more direct about liking it,
Rado učim… is more about gladly doing it.

Could volim also mean I love here, or only I like?

Volim can mean both I like and I love, depending on context.

Volim te. – usually I love you (romantic/strong).
Volim čokoladu. – I like chocolate (or I love, in a casual sense).
Volim učiti hrvatski s tobom. – normally feels like I like learning Croatian with you,
but emotionally, in context (tone of voice, situation), it can be understood as I love doing that with you.

So the verb is the same; English translation depends on how strong you want it to sound.

Why doesn’t Croatian use anything like to before učiti, as in English “to learn”?

Croatian infinitives don’t need a separate word like English to.

English: I like *to learn Croatian.*
Croatian: Volim učiti hrvatski.

Učiti alone already means to learn (the infinitive):

učiti – to learn
pisati – to write
jesti – to eat

So you never add an extra particle like to in front of infinitives in Croatian.

How would the sentence change if I were talking to more than one person (you plural)?

The only change is in the “with you” part.

Instead of s tobom (with you – singular), you use s vama (with you – plural/formal). The rest stays the same:

Volim učiti hrvatski s tobom. – I like learning Croatian with you (one person, informal).
Volim učiti hrvatski s vama. – I like learning Croatian with you (you all / you, formally).

Verb volim is still I like, so it doesn’t change.

How would I say “We like learning Croatian with you”?

You only need to change the verb to the 1st person plural form:

Mi volimo učiti hrvatski s tobom. – We like learning Croatian with you (one person, informal).
Mi volimo učiti hrvatski s vama. – We like learning Croatian with you (plural or formal).

Usually, you can drop mi unless you want emphasis:

Volimo učiti hrvatski s tobom.
Volimo učiti hrvatski s vama.

Is the present tense volim used also for general habits, like English “I like / I usually like”?

Yes. Croatian present tense (for verbs like voljeti, učiti, etc.) is used both for:

Right now actions (I am learning), and
General habits / likes (I learn / I like).

So:

Učim hrvatski. – I am learning Croatian / I learn Croatian.
Volim učiti hrvatski s tobom. – I like (habitually) learning Croatian with you.

Context tells you whether it’s about a single moment or a general statement. Here it’s clearly a general preference.