Learn Hardcore Japanese: sensei no setumei wo kiite, watasi mo nattokusita. - After listening to the teacher’s explanation, I was convinced too.

説明を聞く = listen to an explanation
音楽を聞く = listen to music By contrast, the person you ask is marked with に (先生に聞く = ask the teacher), and the source you hear something from is often から (先生から聞く = hear from the teacher).

Can I say 先生に説明を聞いて?

You will hear it, but it’s ambiguous because に after a person usually means “ask (that person).” To clearly mean “hear the explanation from the teacher,” prefer:

先生の説明を聞いて
先生から説明を聞いて
先生に説明してもらって

What does the て-form in 聞いて do here? Is it “and,” “after,” or “because”?

The て-form connects clauses. Depending on context it can mean:

simple sequence: “did X and then Y,”
or a loose cause: “(on) doing X, Y happened.” With emotion/cognition results (e.g., 驚いた, 嬉しい, 納得した), 〜て often reads as a natural cause: “because/after hearing, I became convinced.”

Why is there a comma after 聞いて?

It just separates the two clauses for readability. The sentence is still correct without it: 先生の説明を聞いて私も納得した。

What nuance does も add in 私も?

も means “also/too.” It implies someone else (or others) were/are convinced, and you are as well. Depending on context, it can also carry an “even I” nuance (e.g., despite difficulty, even I ended up convinced).

Why is 私 placed after the first clause? Could it go at the beginning?

Japanese often sets background first, then states the main point. All of these are natural:

私も先生の説明を聞いて納得した。
先生の説明を聞いて、私も納得した。
先生の説明を聞いて、納得した。 (subject omitted and understood) Note: も replaces は on the same noun. Don’t say 私はも.

What level of politeness is 納得した? Should I use 納得しました?

納得した is plain past (casual/neutral). Use 納得しました (polite) when speaking politely, especially to the teacher. In very polite speech you might use 納得いたしました.

How is 納得する different from 分かる, 理解する, and 了解する?

分かる: to understand (often momentary/awareness). Xが分かった.
理解する: to comprehend (more formal/analytical). Xを理解した.
納得する: to be convinced/to accept as reasonable or satisfactory (pronounced “nattoku”). Xに納得した (accepted X).
了解する: to acknowledge/consent (logistics/requests). Often equals “Got it/Will do.” Avoid with superiors; use 承知しました in formal business.

Could I say 先生の説明に納得した or 先生の説明で納得した?

Yes, both are used with slightly different focus:

先生の説明に納得した = accepted/was convinced by the teacher’s explanation (target of acceptance).
先生の説明で納得した = became convinced because of the teacher’s explanation (cause/instrument). Related patterns: 先生の説明には納得できない (cannot accept), 説明に納得がいく (be satisfied with the explanation).

Is 納得する transitive? How do I say “convince someone”?

納得する is typically “someone becomes convinced.” To make someone else accept:

人を納得させる = to convince/persuade someone
人に納得してもらう = to get someone to accept Also common: 人を説得する (to persuade someone).

Why use 聞く (聞いて) and not 聴く?

Both are read きく. 聞く is the default “hear/listen/ask.” 聴く emphasizes attentive listening (often music, speeches). For 説明, 聞く is standard; 聴く can be used to stress careful listening, but it’s stylistic.

Can I omit 私?

Yes. Subjects are often omitted when clear from context: 先生の説明を聞いて、納得した。 If you need to emphasize inclusion, keep 私も.

How would the meaning change with 聞いたら, 聞いてから, or 聞いた後で?

聞いたら: when/if I heard it, (then) … (often a discovery/surprise feel)
聞いてから: after hearing, then … (clear sequence)
聞いた後で: after hearing (more explicit/formal “after”)
聞いて、…: sequence or gentle cause (most flexible/natural here)

Is 先生 already honorific? Should I say 先生さん? What about ご説明?

先生 is itself an honorific title; don’t add さん to it.
For extra politeness about the explanation, use ご説明: 先生のご説明.
Very polite rephrasing: 先生のご説明を伺って、納得いたしました。 (伺う is the humble form of 聞く/尋ねる)