Los niños juegan sobre la hierba en el parque.

In Spanish, you usually need an article (like el, la, los, las) before a general noun, even when English doesn’t.

• Los niños = the children / the kids
• Just niños (without article) is much less common and usually appears:
  • after hay: Hay niños en el parque. – There are children in the park.
  • in some headlines, labels, or very telegraphic style.

So in a normal sentence like this, los niños is the natural form.

The verb must agree with the subject:

• Subject: los niños → they (3rd person plural).
• Verb jugar (to play) in present tense:
  • yo juego
  • tú juegas
  • él / ella / usted juega
  • nosotros jugamos
  • vosotros jugáis (mainly Spain)
  • ellos / ellas / ustedes juegan

So for ellos (they) / los niños, you need juegan.

Juega would be for él / ella / usted (he / she / you formal).
Jugar is the infinitive: to play (not conjugated).

Yes. Spanish simple present often covers both English forms:

• Los niños juegan sobre la hierba.
  • can mean The children are playing on the grass (right now)
  • or The children play on the grass (in general, habitually)

Context normally clarifies which meaning is intended.
To emphasize “right now,” you can also use the progressive:

• Los niños están jugando sobre la hierba. – The children are playing on the grass (right now).

Both are possible, but there’s a nuance:

• sobre la hierba – literally on (top of) the grass
  Emphasizes physical contact with the surface.
• en la hierba – in/on the grass
  More general: “in the area of the grass,” and can still imply contact.

In many everyday contexts they’re interchangeable.
In Latin America, you’ll also often hear en el césped (“on the lawn / grass”).

Both refer to grass, but usage differs a bit:

• la hierba
  
  • General grass, or sometimes wild grass/weeds.
  • In some countries, hierba can also colloquially mean herb or even marijuana, depending on context.
• el césped
  
  • Usually lawn grass, a maintained area (like in parks, soccer fields, gardens).

For a park, sobre el césped or sobre la hierba can both sound natural; preference varies by country and speaker.

In Spanish, grammatical gender is mostly arbitrary and must be memorized:

• la hierba – feminine
• el parque – masculine

Some general patterns:

• Nouns ending in -a are often feminine: la casa, la mesa, la hierba
• Nouns ending in -o are often masculine: el libro, el perro

But there are many exceptions (el día, la mano, el mapa, etc.), so it’s best to learn nouns together with their article: la hierba, el parque.

Spanish uses definite articles much more than English:

• Los niños juegan sobre la hierba en el parque.
  • Literally: The children play on the grass in the park.

In English we might sometimes drop the for general references (“Kids play on grass”), but in Spanish you normally keep the articles:

• Talking about grass in general here → la hierba
• Talking about a specific or understood park → el parque

Leaving out the articles (Los niños juegan sobre hierba en parque) sounds wrong to native speakers.

Yes, but there’s a nuance:

• niños – specifically children, usually younger kids.
• chicos – can mean kids or young people, sometimes a bit older; in many places it can also just mean guys / boys and girls.

In many Latin American countries chicos is common and natural, but niños is safely understood everywhere and clearly means children.

• en el parque = in the park / at the park (location).
• al parque = to the park (movement / destination).

In this sentence, we’re describing where the children are playing (their location), not where they’re going:

• Los niños juegan en el parque. – The children play in the park.
• Los niños van al parque. – The children go to the park.

Yes. Spanish word order is more flexible than English.

All of these are grammatically fine (with slightly different focus):

• Los niños juegan sobre la hierba en el parque. (neutral, most common)
• Juegan los niños sobre la hierba en el parque. (emphasis can shift to the action juegan)
• Sobre la hierba en el parque juegan los niños. (poetic or very marked style)

In everyday speech, the original order (Los niños juegan...) is the most natural.

Spanish usually drops subject pronouns when the verb ending already shows who the subject is.

• Juegan already tells us it’s ellos / ellas / ustedes.
• So Ellos juegan is not wrong, but it’s only used for emphasis or contrast:
  • Ellos juegan sobre la hierba, pero ellas se sientan en la banca. – They (the boys) play on the grass, but they (the girls) sit on the bench.

With a clear noun subject (los niños), you normally don’t add ellos as well.

Key points:

• j in juegan = a harsh h sound, made in the throat (like in Scottish loch).
• gue in juegan:
  • g before e/i is normally a soft sound (like Spanish j),
  • but with a u (as in gue), it becomes a hard g (like English g in get).
  • Here, gue is pronounced like ge in get (but blended with the j before it).
• Stress is on the first syllable: JUE-gan.

Approximate pronunciation: HWEH-gan (with a strong Spanish h from the throat).

Yes. In modern Spanish:

• h is always silent (except in the ch combination, which is a different sound).
• hierba is pronounced as if it were ierba.

So hierba ≈ YEHR-ba in Latin American pronunciation (with a y sound at the start).

Yes. Niños by default refers to children (boys and girls), but if the context is only boys, it can be understood as boys.

Spanish often uses the masculine plural for mixed or undefined gender groups:

• los niños – can be:
  • boys only, or
  • mixed boys and girls.

To specify girls only, you’d say las niñas.