Learn Hardcore German: Die Kinder spielen barfuß auf dem Rasen.

Singular: das Kind
Plural (nominative/accusative): die Kinder You’ll see den Kindern in the dative plural (for example: Ich helfe den Kindern.).

Why can spielen mean “are playing” even though German has no progressive tense?

German uses the simple present (Präsens) for both English simple and progressive aspects. So Die Kinder spielen … can mean “The children play …” or “The children are playing …,” depending on context. To emphasize “right now,” you can add gerade: Die Kinder spielen gerade …. In some regions you’ll hear a colloquial progressive: Die Kinder sind gerade am Spielen.

What part of speech is barfuß? Does it change form?

barfuß is typically an adverb or a predicative adjective. It does not decline: Er läuft barfuß. / Ich bin barfuß. If you need an attributive adjective before a noun, use barfüßig: barfüßige Kinder (“barefoot children”). You can also paraphrase with mit nackten Füßen.

Why is it auf dem Rasen (dative) and not auf den Rasen (accusative)?

auf is a two-way preposition.

Use dative for location (where?): auf dem Rasen = on the lawn (static location).
Use accusative for direction (where to?): auf den Rasen = onto the lawn (movement). Example: Die Kinder laufen auf den Rasen (they run onto the lawn) vs. Die Kinder spielen auf dem Rasen (they play on the lawn).

Is the word order barfuß auf dem Rasen fixed? Can I say auf dem Rasen barfuß?

Both are possible. A common guideline (Te-Ka-Mo-Lo: Temporal–Kausal–Modal–Lokal) puts manner before place, so barfuß (manner) before auf dem Rasen (place) is the default. Die Kinder spielen auf dem Rasen barfuß is also acceptable and can shift emphasis slightly. You can even front for emphasis: Barfuß spielen die Kinder auf dem Rasen.

What gender is Rasen, and why dem?

Rasen (lawn) is masculine: der Rasen. In the dative singular, the article is dem, so auf dem Rasen. Full singular paradigm:

Nominative: der Rasen
Accusative: den Rasen
Dative: dem Rasen
Genitive: des Rasens

What’s the difference between Rasen, Gras, and Wiese?

Rasen: a maintained lawn (mowed, in a yard/park/sports field).
Gras: grass (the plant/cover in general; often uncountable).
Wiese: a meadow or field, typically more natural and less manicured than a lawn.

Why use auf and not in or an here?

auf indicates being on a surface: auf dem Rasen (on the lawn).
in would suggest being inside/within something: im Gras (in the grass) is possible if you picture the grass surrounding the feet.
an usually indicates “at/by/next to” a vertical surface or an edge: am Rasen would mean “at the lawn (edge),” not on it.

Do I have to write barfuß with ß? Is barfuss wrong?

In Germany and Austria, standard spelling is barfuß (with ß after a long vowel). In Switzerland and Liechtenstein, ß isn’t used, so barfuss is standard there. If you’re writing for Germany/Austria, use barfuß.

How do you pronounce the sentence?

Rough guide (IPA in slashes):

Die Kinder: /diː ˈkɪndɐ/
spielen: /ˈʃpiːlən/ (initial sp sounds like “shp”)
barfuß: /ˈbaʁfuːs/ (long “u,” ß = unvoiced s)
auf dem: /aʊ̯f deːm/
Rasen: /ˈraːzən/ (the “s” between vowels is voiced “z”) Put together smoothly: /diː ˈkɪndɐ ˈʃpiːlən ˈbaʁfuːs aʊ̯f deːm ˈraːzən/.

Can auf dem be contracted?

Not in standard writing. aufs is only a contraction of auf das, not auf dem. In casual speech you might hear auf’m Rasen, but write auf dem Rasen in standard German.

Can I drop the article and say Kinder spielen barfuß auf dem Rasen?

Yes, but it changes the meaning. Die Kinder refers to specific children (the ones you and the listener know). Kinder spielen … is more generic or indefinite (“children are playing …,” some children).

Where does nicht go if I want to negate something?

Place nicht before the element you are negating:

Negate the manner: Die Kinder spielen nicht barfuß auf dem Rasen. (They are playing on the lawn, but not barefoot.)
Negate the place: Die Kinder spielen barfuß nicht auf dem Rasen, sondern auf dem Spielplatz.
Negate the whole predicate (neutral): Die Kinder spielen nicht barfuß auf dem Rasen. (context decides what is contrasted)

Does Kinder change in the dative plural?

Yes. Many plural nouns add -n in the dative plural. Kinder becomes Kindern: Ich helfe den Kindern. This does not apply in the original sentence because Kinder is nominative plural (the subject).