Дети любят играть в песочнице.

Дети is the normal plural of ребёнок (child).

This is one of those common Russian nouns with an irregular plural:

• ребёнок = child
• дети = children

So дети любят... means children like...

A learner might expect a more regular plural, but Russian often has irregular plural forms for very common words.

Because the subject дети is plural.

The verb любить (to like / to love) must agree with the subject:

• он / она любит = he/she likes
• они любят = they like

Since дети means children, the verb takes the 3rd person plural form:

• Дети любят = The children like

After любить, Russian often uses an infinitive to say that someone likes doing something.

So:

• любить играть = to like to play
• любить читать = to like to read
• любить плавать = to like to swim

In this sentence:

• Дети любят играть... = Children like to play...

This works much like English like to play.

Because this sentence describes location, not movement toward a destination.

Russian uses different cases after в depending on meaning:

• в + accusative = motion into somewhere
• в + prepositional = being in somewhere

Compare:

• играть в песочнице = to play in the sandbox
• идти в песочницу = to go to / into the sandbox

So here, the children are already playing in that place, which is why Russian uses the prepositional case: в песочнице.

Песочнице is the prepositional singular form of песочница (sandbox).

The basic form is:

• песочница = sandbox

After в when it means in, the noun usually goes into the prepositional case:

• песочница → в песочнице

This is a very common pattern for feminine nouns ending in -а:

• школа → в школе
• комната → в комнате
• песочница → в песочнице

Because песочница is a feminine noun ending in -а, and in the prepositional singular that ending usually changes to -е.

However, because this word has ц before the ending, the spelling is -це, giving:

• песочница → песочнице

This is just part of the normal declension pattern and Russian spelling rules.

So the important thing to remember is:

• dictionary form: песочница
• after в for location: в песочнице

Yes. Любить can mean both to love and to like, depending on context.

In a sentence like this, English usually translates it naturally as:

• Children like playing in the sandbox
• Children like to play in the sandbox

But in context, it can also feel a bit stronger, closer to:

• Children love playing in the sandbox

So любят here expresses enjoyment or fondness, and English may translate it in slightly different ways.

Russian has no articles, so there is no direct equivalent of a / an / the.

That means:

• дети can mean children or the children
• песочнице can mean a sandbox, the sandbox, or just in a sandbox / in the sandbox

The exact meaning depends on context.

So Дети любят играть в песочнице could be understood as:

• Children like to play in the sandbox
• The children like to play in the sandbox

Context tells you which one is intended.

Yes. Russian word order is more flexible than English because the endings show grammatical relationships.

The neutral order here is:

• Дети любят играть в песочнице.

But other orders are possible for emphasis, for example:

• В песочнице дети любят играть.
• Играть в песочнице дети любят.

These versions sound more marked or emphasize different parts of the sentence. For a learner, the original order is the safest and most neutral.

Играть is the general verb to play.

It can be used for:

• playing games
• playing with toys
• children playing
• playing an instrument, in some contexts

In this sentence, играть в песочнице means to play in the sandbox, so it refers to children’s play in general.

This is the natural verb to use here.

The usual stress is:

• де́ти
• лю́бят
• игра́ть
• в песо́чнице

So the sentence is pronounced approximately:

• ДЕ-ти ЛЮ-бят иг-РАТЬ в пе-СО-чни-це

Stress is important in Russian because it is not always predictable, so it is worth learning words together with their stress.