setumei wo kurikaesite kudasai.

を marks 説明 as the direct object of the verb. In other words, it shows that the explanation is the thing being repeated.

So in 説明を繰り返してください, the structure is:

• 説明 = explanation
• を = marks it as the object
• 繰り返して = repeat
• ください = please do

繰り返して is the て-form of 繰り返す.

The て-form is used for several grammar patterns, and here it is being used with ください to make a polite request:

• 繰り返す = to repeat
• 繰り返してください = please repeat

So the sentence is using the common pattern:

Verb in て-form + ください = please do ...

ください makes the sentence into a polite request.

Without it, 繰り返して by itself could sound incomplete or like part of a longer sentence. With ください, it becomes a clear and polite Please repeat it type of expression.

This is a very common and useful pattern in Japanese:

• 読んでください = please read
• 書いてください = please write
• 説明してください = please explain

Yes, it is grammatical and understandable. It means something like Please repeat the explanation.

However, in everyday conversation, Japanese speakers might more often say:

• もう一度説明してください = Please explain it once more
• もう一回説明してください = Please explain it one more time

These often sound more natural in many situations, because instead of asking someone to repeat the explanation, they simply ask them to explain again.

So 説明を繰り返してください is not wrong, but it can sound a little more formal or literal than the alternatives.

Japanese normally puts the verb at the end of the sentence. So the basic order is often:

object + particle + verb

That is why you get:

• 説明を = the explanation
• 繰り返してください = please repeat

This is different from English, which usually puts the verb before the object:

• English: Repeat the explanation
• Japanese: The explanation, please repeat

The subject is omitted, which is very common in Japanese.

From the context and the use of ください, the listener is understood to be the person who should do the action. So the sentence means:

• Please repeat the explanation
• or more naturally, Please repeat your explanation

Japanese often leaves out words like you, I, or it when they are obvious from context.

It is read:

せつめい を くりかえして ください。

Word by word:

• 説明 = せつめい
• を = を, pronounced o
• 繰り返して = くりかえして
• ください = ください

This is a special feature of Japanese. The particle を is almost always pronounced お in modern Japanese, even though it is written with the character を.

So in this sentence:

• written: 説明を
• pronounced: せつめいお

In romanization, it is usually written as o, not wo, when it is the particle.

Here, 説明 is a noun meaning explanation.

Many Japanese words based on Sino-Japanese vocabulary can function as nouns, and some can also be used with する to make verbs.

For example:

• 説明 = explanation
• 説明する = to explain

So compare:

• 説明を繰り返してください = Please repeat the explanation
• もう一度説明してください = Please explain again

Yes, but it means something slightly different.

• 説明してください = Please explain
• 説明を繰り返してください = Please repeat the explanation

The first one asks for an explanation. The second one asks for the same explanation again.

In many real situations, if you did not understand something, もう一度説明してください would often be the most natural way to ask.

Yes. て-form + ください is a standard polite request pattern.

It is polite enough for many normal situations, such as speaking to a teacher, coworker, customer service worker, or someone you do not know well.

If you want to sound even more polite, you could say:

• 説明を繰り返してくださいませんか
• もう一度説明していただけますか

These sound softer and more formal.

The spaces are just for learners. Normal Japanese writing usually does not use spaces between words.

So this would normally be written as:

説明を繰り返してください。

Textbooks and learning materials often add spaces to make the structure easier to see.

Yes. 繰り返す means to repeat in a broad sense. It can be used for actions, words, events, mistakes, and more.

Examples:

• 同じことを繰り返す = to repeat the same thing
• 練習を繰り返す = to repeat practice
• 失敗を繰り返す = to repeat a mistake

So in this sentence, it is being used with 説明, but the verb itself is quite general.