Булл меньше кольца удвоения.

In Russian, the present-tense verb to be is usually omitted.

So:

Булл меньше кольца удвоения
literally has no separate word for is, but it naturally means Bull is smaller than the doubling ring.

This is completely normal in Russian. In the past or future, Russian would use a form of быть:

• Булл был меньше... = Bull was smaller...
• Булл будет меньше... = Bull will be smaller...

Меньше is the comparative form meaning smaller or less.

Here it works like English smaller in X is smaller than Y.

Why not the others?

• маленький = small/little
  This is the basic adjective, not the comparative.
• меньший = smaller/lesser
  This exists, but it is used differently and is often more formal or adjectival, not the usual choice in a sentence like this.

So for a direct comparison, меньше is the normal form:

• A меньше B = A is smaller than B

Also, меньше does not change for gender or number here. It stays the same.

Because меньше is commonly followed by the genitive case in Russian.

The base noun is:

• кольцо = ring

But after меньше, it becomes genitive singular:

• кольца = of the ring

So the structure is basically:

• Булл меньше кольца...
• literally: Bull is smaller than the ring...

This is a standard Russian comparison pattern:

• больше дома = bigger than the house
• меньше машины = smaller than the car

Because it depends on кольцо.

The underlying noun phrase is:

• кольцо удвоения

This is a noun + genitive structure, where удвоения means of doubling or of duplication.

So:

• кольцо = ring
• удвоения = of doubling

Then, when the whole phrase has to follow меньше, the head noun кольцо changes to genitive:

• кольца удвоения

So you get:

• кольцо удвоения → nominative phrase
• кольца удвоения → genitive phrase after меньше

In other words, удвоения is not caused directly by меньше. It is already there because it belongs to кольцо.

Булл is in the nominative case, because it is the subject of the sentence.

It is the thing being described as smaller.

If Булл is a surname or proper name, that is why it is capitalized. In other cases, a masculine surname ending in a consonant would usually decline:

• Булл = nominative
• Булла = genitive
• Буллу = dative

But in this sentence, nominative is the expected form.

Yes. That is also possible.

Russian has two common comparison patterns here:

1. меньше + genitive

   • Булл меньше кольца удвоения

2. меньше, чем + noun/clause

   • Булл меньше, чем кольцо удвоения

The first one is more compact and is very normal.
The second one can sound a bit more explicit, and it is especially useful when the comparison is longer or more complicated.

So both are grammatical, but the version in your sentence uses the shorter genitive pattern.

Yes, but not in the same rigid way as in English.

The most neutral order here is:

• Булл меньше кольца удвоения

This presents:

1. the subject
2. the comparison
3. the thing compared against

Russian word order can change for emphasis, contrast, or style, but this version is the most straightforward one.

So for a learner, this is the safest order to produce.

Grammatically, yes.

What may feel unusual is not the grammar, but the vocabulary combination. Кольцо удвоения sounds technical or specialized rather than everyday.

So a native speaker would probably understand the grammar immediately, but might need context to understand exactly what object or concept is being discussed.

In short:

• grammar: natural
• style/vocabulary: technical or context-dependent

The stress is:

• Булл — one syllable
• мЕньше
• кольцА
• удвоЕния

A rough English-style guide:

• Булл ≈ bool or bull, depending on the intended name
• мЕньше ≈ MYEN-she
• кольцА ≈ kal-TSA
• удвоЕния ≈ ood-va-YE-ni-ya

A learner should pay special attention to:

• the soft нь in меньше
• the stressed final -а in кольца
• the stressed е in удвоения