Learn Hardcore Polish: Wieczorem biorę jedną tabletkę przed snem. - In the evening I take one pill before sleep.

The base noun is wieczór (evening).
wieczorem is the instrumental singular form.
In Polish, some time expressions use the instrumental form without a preposition to mean “in/at [that time of day]”.

Common ones:

rano – in the morning (irregular form)
po południu – in the afternoon (here you do need po)
wieczorem – in the evening
nocą – at night

So you don’t say *w wieczorem. Just wieczorem by itself means in the evening.

Can I move wieczorem to another place in the sentence?

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

Wieczorem biorę jedną tabletkę przed snem.
Biorę wieczorem jedną tabletkę przed snem.
Biorę jedną tabletkę wieczorem przed snem.
(still natural, though the rhythm is slightly different)

Putting wieczorem at the very beginning is common when you want to emphasize when something happens. Moving it later is more neutral or puts more emphasis on the verb/object instead.

Why is it biorę and not wezmę?

Brać and wziąć are an aspect pair:

brać (present: biorę) – imperfective: focuses on the process, habit, or repeated action.
wziąć (future: wezmę) – perfective: focuses on a single, completed act.

In your sentence:

Wieczorem biorę jedną tabletkę przed snem.
= I take one pill in the evening before sleep. (habit, routine)

If you say:

Wieczorem wezmę jedną tabletkę przed snem.
= I will take one pill this evening before sleep. (a specific future occasion)

So biorę is used because we’re talking about a regular routine, not a one‑time future event.

Does biorę mean I take or I am taking?

It can mean both, depending on context.

Polish does not have a separate continuous form like English I am taking. The same present tense form covers:

I take (usually / regularly).
Wieczorem biorę jedną tabletkę przed snem.
= I take one pill in the evening before sleep. (habit)
I am taking (now).
Właśnie biorę tabletkę.
= I am taking a pill right now.

Context and additional words (like zawsze, właśnie, codziennie) tell you whether it’s a habit, a single event, or something happening right now.

Why is it jedną, not jeden or jedna?

Jeden / jedna / jedno / jedną is the number one and it agrees with the noun in:

gender
case

Here:

tabletka is feminine.
In the sentence, tabletkę is the direct object: it’s in the accusative case.
Feminine accusative singular for jeden is jedną.

Patterns:

masculine (inanimate) accusative: jeden
feminine accusative: jedną
neuter accusative: jedno

So:

jedną tabletkę – one pill
jednego psa – one dog (masculine animate)
jedno jabłko – one apple (neuter)

Why is it tabletkę and not tabletka?

Tabletka is a regular feminine noun ending in -a.

Cases:

Nominative (dictionary form, subject): tabletka
Ta tabletka jest duża. – This pill is big.
Accusative (direct object): usually -ę → tabletkę

In your sentence, the pill is what you are taking, so it is the direct object, which must be in the accusative:

Biorę jedną tabletkę. – I take one pill.

That’s why the ending changes from -a to -ę.

What case is snem, and why is it used after przed?

Snem is the instrumental singular form of sen (sleep).

The preposition przed can take:

instrumental (most common): for location or time – being in front of / before something
accusative (less common, mostly with movement): moving to a position in front of something

Here we are talking about time (before sleep), not movement, so we use the instrumental:

przed snem – before sleep
przed szkołą – in front of the school / before school (in time)

So:

sen (nom.) → snem (instr.)
przed snem literally: before (the) sleep.

Why is it przed snem and not *przed sen?

Because przed requires the instrumental case when used in this time‑or location‑related sense.

Base noun: sen (sleep)
Instrumental: snem

*przed sen is ungrammatical in this meaning. Correct options include:

przed snem – before sleep
przed spaniem – before sleeping (using a verbal noun)
przed pójściem spać – before going to sleep
przed pójściem do łóżka – before going to bed

All are natural, but przed snem is the shortest and very common.

Could I say przed spaniem instead of przed snem? Is there a difference?

Yes, you can say both:

Wieczorem biorę jedną tabletkę przed snem.
Wieczorem biorę jedną tabletkę przed spaniem.

Both mean roughly I take one pill in the evening before sleep / before sleeping.

Nuance:

przed snem – a bit more neutral, sounds like before sleep (as a state/event).
przed spaniem – slightly more like before the activity of sleeping, with spaniem as a verbal noun from spać (to sleep).

In everyday speech, they are very close in meaning, and both are fine.

Why is there no ja (I) in the sentence?

Polish is a pro‑drop language, meaning subject pronouns are usually omitted when the verb ending already shows the person.

biorę already tells you it is 1st person singular (I)
(ja biorę, ty bierzesz, on bierze, etc.)

So:

Wieczorem biorę jedną tabletkę przed snem.
normally said, natural

You might add ja for emphasis or contrast:

To ja wieczorem biorę jedną tabletkę przed snem, a nie on.
It’s me who takes one pill in the evening before sleep, not him.

Can I say wieczorami instead of wieczorem? What’s the difference?

Yes, but the meaning changes slightly.

wieczorem – in the evening (this is understood as your usual routine, but grammatically it’s singular)
wieczorami – in the evenings, on evenings in general (plural, more clearly repetitive)

So:

Wieczorem biorę jedną tabletkę przed snem.
I take one pill in the evening before sleep. (habit, but grammatically singular)
Wieczorami biorę jedną tabletkę przed snem.
I take one pill in the evenings before sleep. (clearly emphasizing every evening / on evenings in general)

Both are correct; wieczorami makes the repeated‑action idea even more explicit.