Con tanto ruido, la profesora no se oye bien.

Because oírse here means to be heard.

So La profesora no se oye bien literally works like:

• The teacher does not hear herself well in form,
• but in meaning it is The teacher can’t be heard well / isn’t heard well.

This is a very common Spanish structure called pasiva refleja or a passive-like use of se. It often avoids using a full passive with ser.

Compare:

• La profesora no se oye bien = The teacher can’t be heard well
• La profesora no oye bien = The teacher doesn’t hear well

Those mean different things. Without se, the teacher is the one doing the hearing. With se, the teacher is the one being heard.

Yes. In La profesora no se oye bien, la profesora is the grammatical subject.

A useful way to see it:

• singular subject → se oye
• plural subject → se oyen

For example:

• La profesora no se oye bien
• Las profesoras no se oyen bien

So the verb agrees with la profesora, which shows that la profesora is the subject.

Con tanto ruido means with so much noise or more naturally because of all that noise / with all that noise.

Breakdown:

• con = with
• tanto = so much
• ruido = noise

Here tanto agrees with ruido, which is a singular masculine noun:

• tanto ruido
• tanta música
• tantos coches
• tantas voces

So con tanto ruido sets the situation: because there is so much noise, the teacher cannot be heard well.

Both are possible, but they are not exactly the same in tone.

• mucho ruido = a lot of noise
• tanto ruido = so much noise

Tanto often adds a stronger sense of degree or emphasis. It sounds like the noise level is especially high and is causing the problem.

So:

• Con mucho ruido, la profesora no se oye bien = With a lot of noise, the teacher can’t be heard well
• Con tanto ruido, la profesora no se oye bien = With so much noise, the teacher can’t be heard well

The second one feels a bit more emphatic.

Bien modifies the verb oírse and means well.

So:

• se oye bien = can be heard well / sounds clear
• no se oye bien = can’t be heard well / doesn’t come through clearly

This is very common when talking about how well someone or something can be heard:

• No te oigo bien = I can’t hear you well
• La radio no se oye bien = The radio can’t be heard well / doesn’t sound clear

Here bien refers to clarity, not morality or behavior.

Grammatically, yes, but it sounds unnatural in everyday Spanish.

Spanish usually prefers:

• La profesora no se oye bien

rather than the full passive:

• La profesora no es oída bien

The version with se is much more natural and common in speech and normal writing.

So for a learner, the best choice is definitely:

• La profesora no se oye bien

Good question. Both relate to hearing, but they are not identical.

• oír = to hear
• escuchar = to listen

In this sentence, the idea is about whether the teacher’s voice reaches people’s ears clearly, so oír is the natural verb.

• La profesora no se oye bien = The teacher can’t be heard well

Using escuchar would not sound as natural here, because escuchar usually implies deliberate attention.

Compare:

• No oigo la profesora = I do not hear the teacher
• No escucho a la profesora = I am not listening to the teacher / I’m not paying attention to the teacher

So in this sentence, oír is the right verb.

Because la profesora is the subject here, not a direct object.

The personal a is used before a direct object that is a person:

• Oigo a la profesora = I hear the teacher

But in your sentence:

• La profesora no se oye bien

la profesora is not the object. She is the subject of the passive-like construction, so there is no a.

Yes. Spanish word order is flexible.

You can say:

• Con tanto ruido, la profesora no se oye bien.
• La profesora no se oye bien con tanto ruido.

Both are correct.

The version with Con tanto ruido at the beginning gives the background first and emphasizes the cause or condition. That is very natural in Spanish.

No. It is talking about how well other people can hear the teacher.

This is the key contrast:

• La profesora no oye bien = The teacher does not hear well
• La profesora no se oye bien = The teacher cannot be heard well

So the sentence is about the teacher’s voice not coming through clearly because of the noise, not about the teacher having hearing problems.

Yes, very natural.

A speaker in Spain would easily say:

• Con tanto ruido, la profesora no se oye bien.

It sounds like normal everyday Spanish and would fit naturally in a classroom situation, a meeting, a video call, or any noisy environment.