Ne volim jak čaj; radije pijem blag čaj s medom.

Jak and blag are adjectives describing čaj. Here they appear in the common short form, which is very normal in simple descriptions like this. They also agree with čaj in gender, number, and case: masculine singular.

You may also meet the long forms jaki and blagi in other contexts, but jak čaj and blag čaj are perfectly natural here.

It is in the accusative, because it is the direct object of the verbs volim and pijem.

The reason it looks unchanged is that čaj is a masculine inanimate noun, and in Croatian the accusative singular of masculine inanimate nouns is usually the same as the nominative singular. So:

• nominative: čaj
• accusative: čaj

The same is true for the adjectives here, so jak and blag also stay in the same-looking form.

Yes, this is the regular way to negate a verb in Croatian: you put ne before the verb.

So:

• volim = I like
• ne volim = I do not like

This pattern is very common:

• pijem → ne pijem
• znam → ne znam
• želim → ne želim

Radije is an adverb meaning rather or preferably. With a verb, it expresses preference:

• radije pijem = I’d rather drink / I prefer to drink

So instead of repeating volim, Croatian often uses radije + verb to show what someone prefers doing.

Yes, that would also be natural.

• radije pijem blag čaj s medom = I’d rather drink mild tea with honey
• više volim blag čaj s medom = I prefer mild tea with honey / I like mild tea with honey more

Both are correct. The version with radije pijem focuses a bit more on the action of drinking.

Because pijem is imperfective and fits a general habit or preference. The sentence is talking about what the speaker usually prefers to drink, not about one completed act.

• pijem = I drink / I am drinking / I tend to drink
• popijem = I drink up / I finish drinking

So radije pijem is the natural choice for a general preference.

Because after s meaning with, Croatian uses the instrumental case.

So:

• basic form: med
• instrumental singular: medom

That gives:

• s medom = with honey

This is a very common pattern:

• s mlijekom = with milk
• s prijateljem = with a friend
• s vodom = with water

Both s and sa mean with, but sa is mostly used when pronunciation is easier that way, especially before certain consonant combinations or forms such as mnom.

Before medom, simple s sounds natural, so s medom is the normal form.

Yes. Croatian word order is more flexible than English word order. The sentence as written is neutral and natural:

Ne volim jak čaj; radije pijem blag čaj s medom.

If you change the order, you usually change the emphasis rather than the basic meaning. For example, moving radije or s medom can make those parts stand out more. But for a learner, the given order is a very good default.

The semicolon links two closely related full clauses:

• Ne volim jak čaj
• radije pijem blag čaj s medom

It shows a stronger break than a comma, but not as strong as a full stop. In everyday writing, a full stop would also be possible.

A rough guide:

• čaj sounds like chai
• č sounds like ch in church
• radije sounds roughly like RAH-di-yeh

Also remember that Croatian j is pronounced like English y in yes.