Mošt a květový med jsou místní.

Because the subject is made of two things joined by a:

Mošt a květový med = must/cider and blossom honey

Even though each noun is singular by itself, together they form a plural subject, so Czech uses jsou = are.

• je = is
• jsou = are

A means and.

It simply joins the two nouns:

mošt a květový med = must/cider and blossom honey

Místní is an adjective meaning local.

In this sentence it works as a predicate adjective after the verb být:

• jsou místní = are local

So the structure is:

[subject] + [are] + [adjective]

Because místní is a type of adjective whose nominative forms often look the same across genders and numbers.

So even though the subject is plural, místní still appears as místní.

This can feel strange to English speakers because English adjectives never change, while Czech adjectives usually do. In this case, Czech does have agreement, but the visible form happens to stay the same.

The main words are in the nominative.

• mošt — nominative singular
• med — nominative singular
• květový — nominative singular, matching med
• místní — nominative, used after být

Why nominative?

• Mošt a květový med is the subject
• after být in a sentence like this, the adjective is normally also in the nominative

Because Czech normally uses an adjective to describe the type of honey here.

• květ = flower / blossom
• květový = flower-based / blossom / floral

So:

květový med = blossom honey / floral honey

This is a normal adjective + noun combination in Czech.

Because it has to agree with med.

Med is:

• masculine
• singular
• nominative

So the adjective also takes the masculine singular nominative form:

• květový med

This is standard Czech adjective agreement.

Because Czech does not use articles like English does.

So Czech simply says:

Mošt a květový med jsou místní.

Depending on context, English might translate that as:

• The must/cider and the blossom honey are local
• Must/cider and blossom honey are local

Czech leaves that distinction to the context.

Yes, Czech word order is fairly flexible.

The neutral, straightforward order is:

Mošt a květový med jsou místní.

But other orders are possible for emphasis, for example:

Místní jsou mošt a květový med.

That would sound more like:

What is local is the must/cider and the blossom honey.

So the original sentence is the most neutral and natural basic order.

Mošt usually means pressed fruit juice, especially something like apple must or fresh cider-like juice, depending on context.

It is not the usual everyday word for any kind of juice in general. For general juice, Czech often uses džus or šťáva, depending on context.

So mošt is a more specific word.

Because each item is named in its own normal singular form:

• mošt = one substance/type of product
• květový med = one substance/type of product

When Czech joins them with a, the whole subject becomes plural:

Mošt a květový med = two items together

So the nouns stay singular individually, but the verb becomes plural:

jsou.