nà wèi lǎoshī shuōhuà de shēngyīn bú dà, zài chǎo de jiàoshì lǐ bú tài hǎo tīngqīngchu.

位 is a polite measure word for people, especially when talking about someone respectfully, such as a teacher, guest, or professional.

So:

• 那位老师 = that teacher (respectful/polite)
• 那个老师 = also possible, but less polite and more neutral

Because 老师 is a person and the sentence has a respectful tone, 位 is a very natural choice.

Literally, it means something like:

the sound/voice of that teacher when speaking

A more natural English rendering would be:

• that teacher’s speaking voice
• the volume of that teacher’s voice when speaking

Breakdown:

• 那位老师 = that teacher
• 说话 = to speak
• 的 = links the modifier to the noun
• 声音 = sound / voice

So 说话的声音 means the voice/sound produced when speaking.

说话 means to speak / talk, while 说 often focuses more on saying something.

In 说话的声音, the sentence is talking about the teacher’s speaking voice or how loudly the teacher speaks, so 说话 fits better.

• 说话的声音 = speaking voice / the sound of someone speaking
• 说的声音 would sound less natural here

So this is about the teacher’s manner of speaking, not just one act of saying something.

In both places, 的 links a modifier to a noun.

1. 说话的声音

   • 说话 modifies 声音
   • literally: the voice that comes from speaking

2. 吵的教室

   • 吵 modifies 教室
   • literally: the noisy classroom

So in both cases, 的 works a bit like turning the words before it into something that describes the noun after it.

You can think of it as:

• [modifier] + 的 + noun

Yes, 大 usually means big, but in Chinese it is also commonly used for volume.

So:

• 声音大 = loud
• 声音不大 = not loud
• 声音很大 = very loud

This is a normal Chinese way to talk about sound volume.

Notice that 不大 here usually means not very loud, not necessarily completely silent or extremely quiet.

This is a tone change rule.

Normally 不 is fourth tone: bù.
But when 不 comes before another fourth-tone syllable, it changes to second tone: bú.

So:

• 不大 → bú dà
• 不太 → bú tài

This is called tone sandhi. The character stays the same; only the pronunciation changes.

This phrase means:

in a noisy classroom

Breakdown:

• 在 = at / in
• 吵的教室 = noisy classroom
• 里 = inside

So:

• 在教室里 = in the classroom
• 在吵的教室里 = in a noisy classroom

Chinese often uses 在 + place + 里 to mark where something happens.

It is understandable, but many native speakers would more naturally say:

• 很吵的教室
• 吵闹的教室

Why? Because 吵 by itself can mean noisy, but in this kind of modifier, people often prefer something a little fuller, like 很吵的 or 吵闹的.

So the original is not impossible, but a more natural version might be:

在很吵的教室里
or
在吵闹的教室里

Here, you should not read it as the word 好听 meaning pleasant-sounding.

Instead, parse it like this:

• 不太好 + 听清楚

Here 好 means something like easy to or convenient to.

So:

• 好做 = easy to do
• 好懂 = easy to understand
• 好听清楚 = easy to hear clearly

Therefore:

不太好听清楚 = not very easy to hear clearly

Because Chinese writing has no spaces, this kind of thing can look confusing at first.

听清楚 means to hear clearly or to hear distinctly.

It is a verb + result complement structure:

• 听 = listen / hear
• 清楚 = clear / clearly

Together, they mean that the hearing is clear enough for the words to be distinguished.

Compare:

• 听见 = hear (catch the sound)
• 听得清楚 = can hear clearly
• 听不清楚 = cannot hear clearly
• 听清楚 = hear clearly

In this sentence, the idea is that the teacher’s voice is hard to make out clearly in a noisy classroom.

Yes. In the second clause, the subject is not stated because it is understood from context.

在吵的教室里不太好听清楚 literally feels like:

• In a noisy classroom, [it] is not very easy to hear clearly.

That omitted it could refer to:

• the teacher’s voice
• what the teacher says
• the teacher speaking

Mandarin often leaves out subjects or objects when they are obvious from context.

Chinese often puts time and place information before the main comment or predicate.

So:

• 在吵的教室里 = in a noisy classroom
• 不太好听清楚 = not very easy to hear clearly

This order is very natural in Chinese:

• [location] + [main statement]

It is similar to English sentences like:

• In a noisy classroom, it’s not very easy to hear clearly.

Yes. The original sentence is understandable, but many speakers might say it more naturally as:

• 那位老师说话声音不大，在吵闹的教室里不太容易听清楚。
• 那位老师说话声音不大，在很吵的教室里听不太清楚。

A few notes:

• 说话声音不大 is a slightly smoother way to say speaking voice is not loud
• 不太容易听清楚 sounds very natural for not very easy to hear clearly
• 听不太清楚 is also a common everyday way to express this idea

So the given sentence is fine for learning, but there are more idiomatic alternatives too.