deetto no kasi to merodhii wo oboeta.

の links nouns and shows a relationship between them. Here, デュエットの歌詞 means the lyrics of the duet or the duet’s lyrics.

So the structure is:

• デュエット = duet
• の = linking particle, often like of
• 歌詞 = lyrics

In this sentence, デュエットの naturally applies to both 歌詞 and メロディー, so the whole phrase is understood as the duet’s lyrics and melody.

と connects nouns and means and.

So:

• 歌詞とメロディー = lyrics and melody

This is the standard way to list nouns in Japanese when you mean a complete, definite list.

Because 歌詞とメロディー is treated as one combined object: lyrics and melody.

Japanese often puts the object marker を after the whole noun phrase rather than after each noun separately.

So:

• 歌詞とメロディーを覚えた
• literally: memorized [lyrics and melody]

You would not normally say 歌詞をメロディーを覚えた.

覚えた is the past tense of 覚える.

In this kind of sentence, 覚える usually means:

• to memorize
• to learn
• to remember by heart

So here it suggests that the speaker learned or memorized the lyrics and melody, not just that they were briefly aware of them.

This is different from verbs like:

• 知る = to come to know
• 分かる = to understand

覚える focuses on retaining something in memory.

Because Japanese normally places the verb at the end.

The basic pattern is often:

[topic/subject] [object] [verb]

Here, the object is:

• デュエットの歌詞とメロディーを

And the verb is:

• 覚えた

So the sentence ends with the action, which is very normal in Japanese.

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

If the context is clear, Japanese often leaves out words like:

• I
• he
• she
• we

So 覚えた could mean:

• I memorized
• she memorized
• they memorized

depending on context.

In many beginner translations, this will often be understood as I memorized..., but the Japanese sentence itself does not explicitly say that.

Katakana is commonly used for:

• loanwords from other languages
• foreign names
• sound effects
• emphasis in some cases

Both デュエット and メロディー are loanwords:

• デュエット = duet
• メロディー = melody

By contrast, 歌詞 is a native/Sino-Japanese word, so it is written with kanji.

In natural Japanese, it is understood to modify both.

So this sentence is understood as:

• the duet’s lyrics and melody

not:

• the duet’s lyrics and some separate melody

Japanese often avoids repeating the same modifier if it clearly applies to multiple items.

If someone wanted to be extra explicit, they could repeat it, but that would usually be unnecessary.

Japanese nouns usually do not change form for singular vs. plural.

So 歌詞 can mean:

• lyric
• lyrics

In practice, 歌詞 usually refers to lyrics as a set, especially in music contexts.

Likewise, Japanese often does not mark articles like a, an, or the. Those are supplied by context when translating into English.

Because 歌詞 specifically means song lyrics, while 歌 means song.

Compare:

• 歌 = song
• 歌詞 = lyrics
• メロディー = melody

So if you want to say someone memorized the words of a song, 歌詞 is the correct word.

Yes, depending on context, 覚えた can sometimes be translated as remembered. But in a sentence like this, with lyrics and melody, the most natural meaning is usually:

• memorized
• learned by heart

That is because lyrics and melody are things people commonly practice until they know them.

So although remembered is not impossible, memorized/learned is usually the better interpretation here.

No. Standard Japanese is usually written without spaces between words.

So this would normally appear as:

デュエットの歌詞とメロディーを覚えた。

Spaces are often added in teaching materials to help beginners see the parts more easily.