Veseli me što ćemo zajedno učiti hrvatski.

Veseli me comes from the verb veseliti, which means to make someone happy / to please / to gladden.

So the structure is closer to:

• It makes me happy that...
• I’m happy that...

Croatian often uses this kind of structure for feelings.
So:

• Veseli me što ćemo zajedno učiti hrvatski. = It makes me happy that we’ll learn Croatian together.

By contrast, Ja sam veseo / vesela means I am cheerful / happy in a more general sense, not specifically because of this fact.

Also:

• veseo = masculine
• vesela = feminine

So Veseli me... is a very natural way to express happiness about a specific situation.

me is the unstressed form of ja in the accusative case.

Here, the verb veseliti works like this:

• something makes someone happy

So the thing causing the feeling is the subject, and the person feeling it is in the accusative:

• To me veseli. = That makes me happy.
• Veseli me to. = That makes me happy.

That is why we get me, not mi.

Compare:

• Veseli me... → me = accusative
• Drago mi je... → mi = dative

English learners often expect I am happy, but Croatian is using a different grammatical pattern here.

Here što means that and introduces a subordinate clause.

So:

• Veseli me što ćemo zajedno učiti hrvatski. = It makes me happy that we’ll learn Croatian together.

In other contexts, što can also mean:

• what
• which
• sometimes why/how much, depending on structure

But in this sentence, it is simply a conjunction meaning that.

No, because veseli does not agree with we here.

The subject of veseli is the whole clause:

• što ćemo zajedno učiti hrvatski

That whole clause is treated as a single idea or fact:

• the fact that we will learn Croatian together

Because that whole clause functions as a singular subject, the verb stays in 3rd person singular:

• Veseli me što...

So even though ćemo means we will, that is inside the subordinate clause and does not control the form of veseli.

This is the future tense.

Croatian forms the future with:

• a present-tense form of htjeti (ću, ćeš, će, ćemo, ćete, će)
• • the infinitive

Here:

• ćemo = we will
• učiti = to learn / to study

So:

• ćemo učiti = we will learn

This is a very common future-tense pattern.

Because Croatian usually drops subject pronouns when they are already clear from the verb form.

Here:

• ćemo already tells you the subject is we

So Croatian does not need to say mi unless it wants emphasis or contrast.

Compare:

• Što ćemo zajedno učiti hrvatski. = neutral
• Što ćemo mi zajedno učiti hrvatski. = that we will learn Croatian together with extra emphasis on we

This omission of subject pronouns is very normal in Croatian.

zajedno means together.

In this sentence it modifies the action učiti:

• ćemo zajedno učiti = we will learn together

Its position can be somewhat flexible, for example:

• što ćemo zajedno učiti hrvatski
• što ćemo učiti hrvatski zajedno

Both are possible, though the first sounds more natural here.

Croatian word order is fairly flexible, but small unstressed words like ćemo usually appear near the beginning of their clause, often in second position.

Because Croatian capitalization rules are different from English.

In Croatian, names of languages are normally written with a lowercase letter:

• hrvatski
• engleski
• njemački

So:

• učiti hrvatski = to learn Croatian

This is completely standard in Croatian, even though English uses a capital letter.

In this sentence, it functions like the name of the language, so in practice it means Croatian.

Historically and grammatically, it is related to the adjective Croatian, and you can think of it as short for:

• hrvatski jezik = the Croatian language

But in everyday use, Croatian often simply says:

• učim hrvatski = I’m learning Croatian

So learners often just treat hrvatski here as the language name.

Yes, absolutely. That is also very natural.

Compare:

• Veseli me što ćemo zajedno učiti hrvatski.
• Drago mi je što ćemo zajedno učiti hrvatski.

Both mean something like I’m glad that we’ll learn Croatian together.

A rough difference:

• Veseli me = it makes me happy / it pleases me
• Drago mi je = I’m glad

Drago mi je is extremely common in Croatian and may sound a bit more conversational in many situations.
Veseli me is also perfectly natural and expresses warm positive feeling.

The sentence is fairly flexible, but not completely free.

The neutral version is:

• Veseli me što ćemo zajedno učiti hrvatski.

You may also hear different emphasis patterns, but you must be careful with clitics like me and ćemo, because they have preferred positions.

For example:

• Jako me veseli što ćemo zajedno učiti hrvatski.
• Veseli me što ćemo hrvatski učiti zajedno.

These are possible, but the original sentence is the most straightforward and natural for a learner to model.

So yes, word order can change, but not randomly. Croatian uses word order partly for focus and emphasis, especially with short unstressed words.