Learn Hardcore Polish: Wieczorem mówimy o jutrzejszym planie. - In the evening we talk about tomorrow’s plan.

wieczór is the basic noun (nominative singular): evening.
- e.g. Ten wieczór jest spokojny. – This evening is calm.
wieczorem is the instrumental form, and in this context it works like an adverb of time, meaning in the evening / at night (in the evening time).
- e.g. Wieczorem mówimy… – In the evening we talk…

Polish very often uses the instrumental case of time nouns in this adverb-like way:

rano / rankiem – in the morning
popołudniem – in the afternoon
nocą – at night

So Wieczorem mówimy… is more natural than Wieczór mówimy…, which would be ungrammatical here.

Can I put mówimy at the beginning and say Mówimy wieczorem o jutrzejszym planie?

Yes. Polish word order is quite flexible.

All of these are grammatically correct:

Wieczorem mówimy o jutrzejszym planie.
Mówimy wieczorem o jutrzejszym planie.
O jutrzejszym planie mówimy wieczorem.

The neutral, most typical word order in this sentence is the original one, but changing the order can add emphasis:

Starting with Wieczorem emphasizes when we talk.
Starting with O jutrzejszym planie emphasizes what we talk about.
Starting with Mówimy is a bit more neutral/statement-like: We talk (and the details follow).

What exactly does mówimy mean in terms of tense and person?

mówimy is:

1st person plural: we
Present tense
From the verb mówić – to speak, to talk, to say

So literally mówimy = we talk / we are talking.

However, Polish present tense can also refer to the near future, especially when it’s about plans or schedules:

Jutro o 10 mówimy o projekcie. – Tomorrow at 10 we are talking about the project.

In your sentence:

Wieczorem mówimy o jutrzejszym planie.
can mean:
- In the evenings we talk about tomorrow’s plan. (habitual)
- This evening we’re talking about tomorrow’s plan. (arranged future, depending on context)

Why do we use the preposition o here, and what case does it take?

In this meaning (about something), o always takes the locative case.

o
- locative: o kim? o czym? – about whom? about what?

In the sentence:

o jutrzejszym planie
- jutrzejszym – locative singular masculine (from jutrzejszy – tomorrow’s)
- planie – locative singular masculine (from plan – plan)

So both words are in the locative to agree with o.

Compare:

Mówimy o filmie. – We are talking about the film.
Mówimy o pracy. – We are talking about work.

Why is it o jutrzejszym planie, not o jutro plan?

jutro is an adverb meaning tomorrow. You can’t put it directly after o, because o needs a noun in the locative case, not an adverb.

So:

Incorrect: o jutro plan
Correct idea: use a noun phrase that means the plan for tomorrow:
- o jutrzejszym planie – about tomorrow’s plan (literally: about the tomorrow-ish plan)
- or: o planie na jutro – about the plan for tomorrow

jutrzejszy is an adjective derived from jutro and can be declined:

jutrzejszy plan (nominative)
o jutrzejszym planie (locative, after o)

What’s the difference between jutrzejszym planie and planie na jutro?

Both mean plan for tomorrow, but the structure is slightly different:

jutrzejszy plan / o jutrzejszym planie
- Adjective-based: jutrzejszy (tomorrow’s).
- Sounds very natural and a bit more compact.
- Literally: tomorrow’s plan.
plan na jutro / o planie na jutro
- Prepositional phrase with na (for).
- Also very common and totally correct.
- Literally: plan for tomorrow.

In your sentence you could say:

Wieczorem mówimy o jutrzejszym planie.
Wieczorem mówimy o planie na jutro.

Both sound natural, with only a slight stylistic difference.

Why is there no word for the in this sentence?

Polish does not have articles (a/an/the). The definiteness or indefiniteness is understood from context, not from a separate word.

So plan can mean:

a plan
the plan
our plan depending on the situation and what both speakers know.

Wieczorem mówimy o jutrzejszym planie. could translate as:

In the evening we talk about *the plan for tomorrow.*
In the evening we talk about *our plan for tomorrow.* English has to choose an article; Polish does not.

Why is jutrzejszym ending in -ym? How is it formed?

jutrzejszym is the locative singular masculine form of the adjective jutrzejszy (tomorrow’s).

Pattern:

Base adjective: jutrzejszy – tomorrow’s
Masculine singular nominative: jutrzejszy plan – tomorrow’s plan
Masculine singular locative: o jutrzejszym planie

The -ym ending is typical for masculine/neuter adjectives in the locative (and also instrumental) singular:

nowy plan → o nowym planie
ważny temat → o ważnym temacie
jutrzejszy plan → o jutrzejszym planie

What does Wieczorem express exactly—habit (every evening) or just one particular evening?

By itself, Wieczorem could mean:

habitual: In the evenings / In the evening (generally, as a routine)
one specific: This evening or tonight

The exact meaning depends on context and sometimes intonation:

With additional adverbs like zwykle, zawsze, często it’s clearly habitual:
- Wieczorem zawsze mówimy o jutrzejszym planie. – In the evenings we always talk about tomorrow’s plan.
In a context of making plans for today, it’ll sound like this evening:
- Rano idziemy na zakupy, a wieczorem mówimy o jutrzejszym planie.
  – In the morning we go shopping, and in the evening we talk about tomorrow’s plan.

What’s the difference between mówimy o planie and rozmawiamy o planie?

Both can often be translated as we talk about the plan, but there’s a nuance:

mówić o czymś – to say/talk/speak about something
Focus is more on the act of saying or discussing content.
rozmawiać o czymś – to converse, to have a discussion about something
Emphasizes two-way conversation, interaction between people.

In your sentence, both are fine:

Wieczorem mówimy o jutrzejszym planie.
Wieczorem rozmawiamy o jutrzejszym planie.

The second one highlights more clearly that it’s a conversation between people, not, for example, one person giving a monologue.

How do you pronounce the tricky parts: ó in mówimy and ą in wieczorem (if it were there), and j in jutrzejszym?

For this sentence specifically:

mówimy – the ó is pronounced like u:
- mówimy ≈ muwimy (IPA: /muˈvʲimɨ/)
wieczorem – there is e, not ą, but for reference:
- nasal ą usually sounds like [ɔ̃] or [ɔw̃]/[on] depending on context.
jutrzejszym:
- j is like English y in yes.
- rz is usually like the French j in jouer or the s in English measure (IPA: /ʐ/).
- Roughly: yoo-tzheh-shym (more precisely: /juˈtʐɛjʂɨm/).

So the whole sentence, roughly:

Wieczorem mówimy o jutrzejszym planie. ≈ Vyeh-CHO-rehm MOO-vee-mih oh yoo-TRZHEH-shym PLAH-nyeh.