Вісімдесят людей у парку.

In Ukrainian, the verb to be is usually omitted in the present tense.

So:

• Вісімдесят людей у парку. = Eighty people are in the park.

A more literal breakdown is something like:

• Eighty people in the park

But in natural English, we add are.

In past or future, Ukrainian does use forms of to be, but in the present tense it is normally left out.

Because numbers like 5 and higher usually require the noun in the genitive plural.

So:

• 1 person: a singular form
• 2, 3, 4 people: usually a different plural pattern
• 5+ people: genitive plural

Here, вісімдесят means 80, so людей is the correct form.

Compare:

• одна людина = one person
• дві людини = two people
• п’ять людей = five people
• вісімдесят людей = eighty people

So люди is not the right form after вісімдесят.

Парку is in the locative case.

The prepositions у and в often mean in or at, and when they show location, the noun usually goes into the locative:

• у парку = in the park

The dictionary form is:

• парк = park

After у / в for location, it becomes:

• у парку

So the ending changes because the sentence is talking about where the people are.

This is an important location-vs-motion distinction.

• у парку = in the park / at the park
  
  • location
  • uses the locative
• в парк = into the park / to the park
  
  • direction or movement
  • uses the accusative

So:

• Вісімдесят людей у парку. = Eighty people are in the park.
• Вісімдесят людей ідуть в парк. = Eighty people are going to the park.

Yes, у and в usually mean the same thing here. The choice is often made for ease of pronunciation and smoother sound.

Ukrainian alternates between them to avoid awkward clusters of consonants or vowels.

So both of these can mean the same thing:

• у парку
• в парку

In this sentence, у парку simply sounds smoother after людей.

This kind of alternation is very common in Ukrainian.

It can function as a complete sentence in Ukrainian.

Because present-tense to be is usually omitted, a sentence like this is perfectly normal and complete:

• Вісімдесят людей у парку.

It means:

• Eighty people are in the park.

So even though it may look like just a noun phrase to an English speaker, in Ukrainian it works as a full sentence.

Yes. Ukrainian word order is fairly flexible.

This sentence can be rearranged depending on what you want to emphasize:

• Вісімдесят людей у парку. = neutral
• У парку вісімдесят людей. = emphasizes the location first, like There are eighty people in the park
• Людей у парку вісімдесят. = emphasizes the number

The basic meaning stays similar, but the focus changes.

A simple learner-friendly approximation is:

• VEE-seem-deh-syat lyu-DEY oo PAR-koo

A few helpful points:

• вісімдесят = eighty
• людей has a lyu sound at the start
• ей in людей sounds roughly like ay in day
• у парку is pronounced smoothly together

If you want, you can think of the rhythm like this:

• ВІ-сім-де-СЯТЬ лю-ДЕЙ у ПАР-ку

80 is not special in that respect. It follows the same general rule as other numbers from 5 upward: the noun usually takes the genitive plural.

Examples:

• п’ять людей = five people
• десять людей = ten people
• двадцять людей = twenty people
• вісімдесят людей = eighty people

But compare with smaller numbers:

• одна людина = one person
• дві людини = two people
• три людини = three people
• чотири людини = four people

So learners often need to memorize this pattern:

• 1 → singular
• 2–4 → a plural form like людини
• 5+ → genitive plural, like людей