Bu üzümler çok tatlı.

In Turkish, bu can mean both this and these. It does not change form for singular vs. plural.

So:

• bu üzüm = this grape
• bu üzümler = these grapes

The noun tells you whether it is singular or plural, not bu.

Üzümler comes from:

• üzüm = grape
• -ler / -lar = plural ending

So:

• üzüm = grape
• üzümler = grapes

The plural suffix appears as -ler here because of vowel harmony. Since the last vowel in üzüm is ü (a front vowel), the plural ending is -ler, not -lar.

In Turkish, in the present tense, sentences like X is Y or X are Y often do not need an explicit word for is/are.

So:

• Bu üzümler çok tatlı. literally looks like These grapes very sweet.
• But in natural English, it means These grapes are very sweet.

This is very normal in Turkish. The idea of are is understood.

Here, çok means very.

So çok tatlı means very sweet.

A useful thing to know is that çok can also mean many/a lot, depending on what it modifies:

• çok tatlı = very sweet
• çok üzüm = many grapes / a lot of grapes

So the meaning depends on context and sentence structure.

Here, tatlı is the predicate adjective: it tells you what the grapes are like.

The structure is:

• Bu üzümler = subject
• çok tatlı = predicate

So the sentence pattern is basically:

• These grapes + are + very sweet

In Turkish, this kind of sentence often places the descriptive part at the end:

• Bu üzümler çok tatlı.

That is completely normal.

Here, tatlı is an adjective meaning sweet.

It can also be used as a noun in other contexts, for example to mean dessert or sweet thing, but in this sentence it is clearly an adjective describing üzümler.

So here:

• tatlı = sweet

The letter ü is a front rounded vowel. English does not have an exact equivalent, but it is similar to the vowel sound in French tu or German über.

A rough guide:

• üzüm sounds roughly like ew-zewm, but with rounded lips
• üzümler is roughly ew-zewm-ler, again with that ü sound

A few pronunciation notes:

• ü is always pronounced clearly
• r in Turkish is usually lightly tapped or rolled
• stress in Turkish often falls toward the end, though in everyday speech this can vary

Turkish does not use articles the same way English does.

There is no direct equivalent of the in this sentence. Definiteness is often understood from context or from words like bu.

Because the sentence has bu, the noun phrase is already specific:

• bu üzümler = these grapes

So you do not need a separate word for the.

Yes. Üzümler çok tatlı is also a correct sentence.

It means The grapes are very sweet or Grapes are very sweet, depending on context.

Adding bu makes it more specific:

• Üzümler çok tatlı. = The grapes are very sweet. / Grapes are very sweet.
• Bu üzümler çok tatlı. = These grapes are very sweet.

So bu points to particular grapes.

Because this sentence is talking about more than one grape.

Compare:

• Bu üzüm çok tatlı. = This grape is very sweet.
• Bu üzümler çok tatlı. = These grapes are very sweet.

The singular noun is üzüm. The plural noun is üzümler.

So the Turkish sentence makes the number very clear.

The sentence follows a common Turkish pattern:

• subject + predicate

Here:

• Bu üzümler = subject
• çok tatlı = predicate

So:

• Bu üzümler çok tatlı.

You may hear that Turkish is an SOV language, and that is true for many verb sentences. But in sentences without an expressed verb like this one, it is easiest to think of the pattern as:

• topic/subject first
• description at the end

Yes, when bu is used as a determiner meaning this/these, it normally comes before the noun:

• bu üzüm = this grape
• bu üzümler = these grapes

That is the normal position.

Because üzümler is the subject of the sentence, so it is in the basic dictionary form, often called the nominative form.

Turkish case endings appear when a noun has a role like:

• direct object
• location
• direction
• source
• possession-related functions in some structures

But here the grapes are simply the thing being described, so no extra case ending is needed. The word is just:

• üzümler = grapes

Yes. Tatlı literally means sweet, but it can also be used more broadly, a bit like English.

For example, it can describe:

• food: çok tatlı = very sweet
• a person, baby, or animal: çok tatlı = very sweet / very cute / lovely

In this sentence, because the noun is grapes, the meaning is clearly about taste.