彼は歌が上手です。
- He is good at singing.

彼は歌が上手です。 meaning: He is good at singing.

The sentence follows a subject-topic-adjective pattern. Japanese sentences often have a topic indicated by the particle は (wa), followed by the subject, and then an adjective or verb phrase. ⚫︎ Subject: 彼 (kare - he) ⚫︎ Topic Marker: は (wa) ⚫︎ Subject: 歌 (uta - singing) ⚫︎ Particle: が (ga) - indicates the subject of the adjective ⚫︎ Adjectival noun: 上手 (jouzu - good at) ⚫︎ Copula: です (desu) - polite form of "to be"

は (wa) marks the topic of the sentence. The topic is what the sentence is about. ⚫︎ It often translates to "as for" or "regarding." ⚫︎ In this sentence, 彼 (kare - he) is the topic. The sentence is about "him".

が (ga) marks the subject of the adjective or verb. ⚫︎ In this sentence, 歌 (uta - singing) is the subject of the adjectival noun 上手 (jouzu - good at). ⚫︎ It shows what he is good at.

Adjectival nouns (also known as na-adjectives) describe nouns. They always require です (desu) to make the sentence polite. ⚫︎ 上手 (jouzu - good at) is an adjectival noun. It modifies the topic歌 (uta-singing). ⚫︎ です (desu) is a polite form of the copula "to be". It indicates politeness. ⚫︎ Without です the sentence would be "彼は歌が上手だ。" (kare wa uta ga jouzu da - He is good at singing), which is more casual.

This is a common fixed expression used to express someone's skill or ability. ⚫︎ ～ represents the thing or activity someone is good at. ⚫︎ The particle が (ga) is essential in this expression. ⚫︎ Examples: ⚫︎ 彼は英語が上手です。 (kare wa eigo ga jouzu desu - He is good at English.) ⚫︎ 私は料理が上手です。 (watashi wa ryouri ga jouzu desu - I am good at cooking.)