Learn Hardcore Croatian: To nije problem; imamo drugi plan. - That is not a problem; we have another plan.

Affirmative: To je problem. (That is a problem.)
Negative: To nije problem. (That is not a problem.) Other present-tense forms of biti for reference: sam, si, je, smo, ste, su; negatives: nisam, nisi, nije, nismo, niste, nisu.

What exactly does to mean here? How is it different from ovo and ono?

to is a neutral demonstrative pronoun often used for “that/it” referring to something already known from context.

ovo = this (near the speaker)
to = that/it (neutral/default)
ono = that over there/that (distant or less immediate) All three can be subjects: Ovo/To/Ono nije problem.

Where is the English article “a” in “not a problem”?

Croatian has no articles. Predicate nouns after je/nije stand bare: To je problem. / To nije problem. Context supplies the “a/the” meaning.

Why is it problem and not problema after nije?

After je/nije, the noun is in the nominative case (predicate nominative): To nije problem.
Genitive appears with nema (“there is no”): Nema problema. So:

To nije problem. (It isn’t a problem.)
Nema problema. (There’s no problem / No problem.)

Why a semicolon? Could I use a comma or a period instead?

All three are possible, with slight stylistic differences:

To nije problem. Imamo drugi plan. Neutral, safest.
To nije problem; imamo drugi plan. Closer link than a period; formal.
To nije problem, imamo drugi plan. Common in informal writing; prescriptive guides prefer a semicolon or period when there is no conjunction.

What is imamo? How do I negate it?

It’s 1st person plural present of imati (to have): imam, imaš, ima, imamo, imate, imaju.
Negation fuses ne + imati: nemam, nemaš, nema, nemamo, nemate, nemaju.
So: Imamo drugi plan. / Nemamo drugi plan.

Can/should I include mi (we)?

Subject pronouns are usually dropped because the verb ending shows the person. Imamo drugi plan is normal. Mi imamo drugi plan adds emphasis or contrast (we, as opposed to someone else).

Can the word order change?

Yes, Croatian allows flexibility for emphasis:

To nije problem; imamo drugi plan. Neutral.
Nije to problem; imamo drugi plan. Emphasizes “not a problem.”
To nije problem; drugi plan imamo. Emphasizes “another plan.”
Mi imamo drugi plan. Emphasizes the subject “we.”

Why drugi and not drugo? How does agreement work?

Adjectives agree with the noun’s gender, number, and case.

plan is masculine singular, so: drugi plan.
Feminine example: druga ideja (another idea).
Neuter example: drugo rješenje (another solution). Using drugo plan would be ungrammatical.

Does drugi mean “second” or “another”?

Both, depending on context:

Ordinal “second”: drugi kat (the second floor).
“Another/other/different”: drugi plan = another/alternative plan. Context tells you which reading is intended.

Can I say još jedan plan instead of drugi plan? What’s the difference?

drugi plan focuses on an alternative or the second in a set; it can imply contrast with the first.
još jedan plan literally “one more plan,” highlighting addition (an extra plan), without necessarily contrasting with a first.
Both are fine; pick based on nuance.

How do I say it in the plural: “We have other plans”?

Use accusative plural:

Imamo druge planove.
Notes:
Masculine inanimate nouns like plan take -ove/-eve in the accusative plural (planove).
The adjective changes to druge in the accusative plural.

Is nije problem a fixed expression like “No problem”?

Yes, you’ll hear (To) nije problem to reassure someone. Even more idiomatic in many contexts is Nema problema (“No problem/No worries”), which also works as a casual response to “thank you.”

How do I intensify it to “That’s not any kind of problem at all”?

Use nikakav:

To nije nikakav problem. (It’s no problem at all.)
You can also say: Uopće nije problem. (It’s not a problem at all.)

How would I say “That’s the problem”?

To je problem.
To focus it more strongly: Upravo je to problem. or E to je problem.

Any pronunciation tips for this sentence?

Approximate English-friendly rendering:

To: “toh”
nije: “NEE-ye”
problem: “PRO-blem”
imamo: “ee-MA-mo”
drugi: “DROO-gee”
plan: “plahn”
Stress is typically on the first syllable of each word here; exact accents vary by dialect.

Could I join the clauses with a conjunction?

Yes. To nije problem jer imamo drugi plan. (That’s not a problem because we have another plan.)
You could also say … pa imamo drugi plan (“so/therefore we have…”). Use ali (“but”) only for contrast; it’s not needed in this sentence.