Learn Hardcore Polish: Nasza przewodniczka pokazuje dzieciom bezpieczną ścieżkę przez łąkę. - Our guide female shows the children a safe path through the meadow.

przewodniczka is the feminine form of przewodnik (guide). It is grammatically feminine.
The possessive nasz / nasza / nasze changes to match the gender of the noun:
- nasz przewodnik – our (male / generic) guide
- nasza przewodniczka – our (female) guide
- nasze dziecko – our child

So because the noun is feminine (przewodniczka), the possessive must also be feminine: nasza.

What is the difference between przewodnik and przewodniczka?

Both mean guide, but they differ by grammatical and natural gender:

przewodnik – grammatically masculine; usually refers to a male guide, or can be generic (especially in older usage).
przewodniczka – grammatically feminine; specifically a female guide.

In modern, everyday Polish, if you explicitly know the guide is female, przewodniczka is very natural and common. If you talk about the profession in general (e.g. “a mountain guide must be well trained”), przewodnik is more typical.

Why is dzieciom in the dative case? Why not the same form as the basic plural dzieci?

The verb pokazywać (to show) takes two objects:

komu? – to whom? (dative)
co? – what? (accusative)

So the pattern is:
pokazywać komu? co? – “to show someone something”

In the sentence:

dzieciom – dative plural of dziecko (to the children) → indirect object
bezpieczną ścieżkę – accusative singular (a safe path) → direct object

That’s why you need dzieciom (dative), not just dzieci.
Forms of dziecko are a bit irregular:

singular:
- nominative: dziecko (child)
- dative: dziecku (to the child)
plural:
- nominative/accusative: dzieci (children)
- dative: dzieciom (to the children)

What exactly is the role of dzieciom in the sentence?

Dzieciom is the indirect object: it answers “to whom?”:

Nasza przewodniczka pokazuje dzieciom...
→ Our guide shows the children...

So structurally it’s:

subject: nasza przewodniczka (our guide)
verb: pokazuje (shows / is showing)
indirect object (dative): dzieciom (to the children)
direct object (accusative): bezpieczną ścieżkę (a safe path)
adverbial phrase: przez łąkę (through the meadow)

Why is it bezpieczną ścieżkę, with these endings -ą and -ę?

Both bezpieczną (safe) and ścieżkę (path) are in the accusative singular feminine and must agree with each other:

base forms (nominative):
- bezpieczna ścieżka – a safe path
in the sentence (accusative, object of “pokazuje”):
- bezpieczną ścieżkę

Typical pattern for a feminine noun like ścieżka:

nominative: -a → ścieżka
accusative: -ę → ścieżkę

The adjective follows:

nominative feminine: bezpieczna
accusative feminine: bezpieczną

Could I say bezpieczna ścieżka instead of bezpieczną ścieżkę here?

Not in this sentence. You need the accusative because ścieżkę is the direct object of the verb pokazuje.

bezpieczna ścieżka – nominative (used mostly for the subject of the sentence)
- e.g. Bezpieczna ścieżka prowadzi przez łąkę.
  “A safe path leads through the meadow.”
bezpieczną ścieżkę – accusative (used here as the object)
- Nasza przewodniczka pokazuje bezpieczną ścieżkę.
  “Our guide is showing a safe path.”

So with pokazuje co? you must use bezpieczną ścieżkę, not bezpieczna ścieżka.

Why is it przez łąkę, and what case does przez require?

The preposition przez (through, across) always takes the accusative case.

łąka – meadow (nominative)
łąkę – accusative (after przez)

So:

przez łąkę – through the meadow
przez las – through the forest
przez most – across the bridge

Other prepositions of movement can take different cases, for example:

do
- genitive: do lasu – to the forest
po
- locative/accusative (depending on meaning): po łące – around/on the meadow (walking around on it)

Why do we say łąkę and not łąka? And how do you pronounce ą?

Łąkę is the accusative singular of łąka (meadow), required by przez and also by verbs of motion or position when they take an object.

nominative: łąka – “meadow” (subject)
accusative: łąkę – “meadow” (object, after przez)

Pronunciation of ą:

ą is a nasal vowel, roughly like “on” in French bon or “own” but nasalized.
In łąka, it’s pronounced approximately like [won-ka], but with a nasal ą, not a clear “on”.
In łąkę, before k, it’s also nasal; many learners approximate it as “won-keh” but with nasal quality on the vowel.

Native pronunciation is smoother and more nasal than any simple English approximation.

Does pokazuje mean “shows” or “is showing”? Which English tense is it?

Polish present tense often covers both English present simple and present continuous.

So pokazuje can mean:

“(she) shows” – habitual / repeated action
“(she) is showing” – action happening right now

In context:

Nasza przewodniczka pokazuje dzieciom bezpieczną ścieżkę...
Could be:
- “Our guide is showing the children a safe path...” (right now)
- “Our guide shows the children a safe path...” (as a routine, e.g. on every trip)

The exact nuance comes from context, not from verb form change.

What aspect is pokazuje, and could we use pokazała instead?

pokazuje is imperfective, present tense, 3rd person singular of pokazywać (to be showing / to show in general).
pokazała is perfective, past tense, feminine, 3rd person singular of pokazać (to show once, completed).

Use:

Nasza przewodniczka pokazuje...
→ happening now / in progress / general behavior.
Nasza przewodniczka pokazała dzieciom bezpieczną ścieżkę...
→ “Our (female) guide showed the children a safe path...” (one finished event in the past).

So you cannot just swap pokazuje and pokazała: it changes both time (present vs past) and aspect (ongoing/general vs completed).

Is the word order fixed, or could I move things around in this sentence?

Polish word order is more flexible than English, though not totally free. The neutral, clear order is:

Nasza przewodniczka pokazuje dzieciom bezpieczną ścieżkę przez łąkę.

You can move elements for emphasis, for example:

Przez łąkę nasza przewodniczka pokazuje dzieciom bezpieczną ścieżkę.
(Fronting przez łąkę for emphasis on the location.)
Dzieciom nasza przewodniczka pokazuje bezpieczną ścieżkę przez łąkę.
(Emphasis on to the children, perhaps contrasting with someone else.)

However:

Very unusual orders like Przewodniczka nasza dzieciom pokazuje... sound old-fashioned or poetic.
Unlike English, the grammatical roles are mostly marked by cases (naszej przewodniczce, dzieciom, ścieżkę, łąkę), so moving words does not change who does what; it changes focus/emphasis and sometimes style.

Could we leave out nasza and just say Przewodniczka pokazuje dzieciom...?

Yes, you can omit nasza if it’s clear from context who you’re talking about.

Nasza przewodniczka pokazuje...
– “Our guide is showing...”
Przewodniczka pokazuje...
– “The guide is showing...” (or just “A guide is showing...”, depending on context)

Polish has no articles (the, a), so the possessive nasza can play a role similar to saying our or specifying which guide you mean. Dropping nasza makes it a bit more general or less specific to “us”.

Is dzieciom always plural? What is the singular form “to the child”?

Yes, dzieciom is always dative plural: to the children.

From dziecko (child):

singular:
- nominative: dziecko – child
- dative: dziecku – to the child
plural:
- nominative/accusative: dzieci – children
- dative: dzieciom – to the children

So:

Przewodniczka pokazuje dziecku ścieżkę.
– The guide shows the path to the child.
Przewodniczka pokazuje dzieciom ścieżkę.
– The guide shows the path to the children.