Te maliny są dziś kwaśne, więc dzieci wolą truskawki.

Te means these.

It agrees with maliny (raspberries), which is a plural non-masculine-personal noun, so the correct form is te.

• ta malina = this raspberry
• te maliny = these raspberries

So Te maliny literally means These raspberries.

Because the sentence is talking about raspberries in general as a plural group, not one raspberry.

• malina = raspberry
• maliny = raspberries

Since te is plural here, the noun also has to be plural: te maliny.

Są is the 3rd person plural form of być (to be).

The subject is te maliny (these raspberries), which is plural, so Polish uses the plural verb:

• jest = is
• są = are

So:

• Te maliny są kwaśne = These raspberries are sour

Yes, Polish often omits to be in the present tense when identifying something, especially in sentences like:

• To moja siostra = This is my sister

But with many ordinary adjective sentences, especially ones like X is Y, Polish usually keeps the verb:

• Maliny są kwaśne = The raspberries are sour

So in this sentence, są is natural and expected.

Dziś means today.

In Te maliny są dziś kwaśne, it tells us that the raspberries are sour today / today in particular.

Polish word order is fairly flexible, so you may also see:

• Te maliny dziś są kwaśne
• Dziś te maliny są kwaśne

But Te maliny są dziś kwaśne is very natural.

Also, dziś and dzisiaj both mean today. Dziś is just a bit shorter.

Because adjectives in Polish must agree with the noun they describe.

Maliny is a plural noun, and it is not masculine personal, so the adjective takes the plural non-masculine-personal form -e:

• kwaśny = sour (singular masculine)
• kwaśna = sour (singular feminine)
• kwaśne = sour (plural non-masculine-personal, and also singular neuter)
• kwaśni = sour (plural masculine personal)

Since maliny is plural and not masculine personal, the correct form is kwaśne.

Więc means so, therefore, or thus.

It connects the two ideas:

• the raspberries are sour today
• as a result, the children prefer strawberries

So:

• Te maliny są dziś kwaśne, więc dzieci wolą truskawki. = These raspberries are sour today, so the children prefer strawberries.

It is a very common everyday connector.

Because więc introduces a result clause, and in standard Polish punctuation it is separated by a comma.

So the structure is:

• statement 1 + , więc
  • statement 2

That is why the sentence is written:

• Te maliny są dziś kwaśne, więc dzieci wolą truskawki.

Dzieci means children, so it is plural.

It is the plural form of dziecko (child), but this is an irregular noun, so you cannot just guess it from the singular.

Important forms:

• dziecko = child
• dzieci = children

Even though dzieci refers to people, it does not behave like ordinary masculine-personal plurals in every way, so learners often just need to memorize it as a special plural form.

Because wolą is the 3rd person plural form of woleć (to prefer).

Since dzieci is plural, the verb must also be plural:

• dziecko woli = the child prefers
• dzieci wolą = the children prefer

So:

• dzieci wolą truskawki = the children prefer strawberries

The dictionary form is woleć, which means to prefer.

Some useful forms are:

• wolę = I prefer
• wolisz = you prefer
• woli = he/she/it prefers
• wolimy = we prefer
• wolicie = you all prefer
• wolą = they prefer

So wolą is simply they prefer.

Here truskawki is the accusative plural form, because it is the direct object of wolą (prefer).

But for many feminine plural inanimate nouns, the nominative plural and accusative plural look the same.

So:

• nominative plural: truskawki
• accusative plural: truskawki

That is why it looks unchanged.

Because Polish has no articles like English the or a/an.

So Polish often expresses meaning without an article:

• maliny can mean raspberries, the raspberries, or sometimes just raspberries in general
• dzieci can mean children or the children
• truskawki can mean strawberries or the strawberries

Context tells you which meaning is intended.

Almost:

• Te = these
• maliny = raspberries
• są = are
• dziś = today
• kwaśne = sour
• więc = so
• dzieci = children
• wolą = prefer
• truskawki = strawberries

A very literal version would be:

These raspberries are today sour, so children prefer strawberries.

But natural English would usually be:

These raspberries are sour today, so the children prefer strawberries.

Polish word order is more flexible than English, because endings show grammatical relationships.

The original sentence is very natural:

• Te maliny są dziś kwaśne, więc dzieci wolą truskawki.

But other orders are possible, especially for emphasis:

• Dziś te maliny są kwaśne, więc dzieci wolą truskawki.
• Te maliny są kwaśne dziś, więc dzieci wolą truskawki.
  (possible, but less neutral)

The original version sounds like a normal neutral statement.

A rough guide:

• dziś sounds approximately like jish or dzhish, but softer
• więc sounds roughly like vyents, with a nasal vowel in ię

A few pronunciation notes:

• dz in dziś is a single consonant sound
• ś is a soft sh-like sound
• ę in więc is a nasal vowel, though in real speech its pronunciation can vary depending on what follows

If you are a beginner, it is fine to first aim for an approximate pronunciation and improve it with listening practice.

Usually yes in a sentence like this.

Kwaśny / kwaśna / kwaśne often means:

• sour
• acidic
• sometimes tart

So for fruit, kwaśne is very naturally translated as sour or sometimes too tart depending on context.

Here sour is the best basic translation.

Because Polish, like English, often links cause and result smoothly in one sentence.

• Te maliny są dziś kwaśne, więc dzieci wolą truskawki. = The raspberries are sour today, so the children prefer strawberries.

You could split it into two sentences:

• Te maliny są dziś kwaśne. Dzieci wolą więc truskawki.

But the original version is more natural as one connected thought.