No quiero cometer errores cuando hablo en público.

Because after querer + another action, Spanish normally uses the infinitive of the second verb.

• quiero comer = I want to eat
• quiero estudiar = I want to study
• quiero cometer errores = I want to make mistakes

So quiero cometer is the normal structure for to want to do something.

In Spanish, no usually goes right before the conjugated verb to make the sentence negative.

Here, the main conjugated verb is quiero, so:

• No quiero... = I do not want...

You would not normally say Quiero no cometer errores unless you specifically want to emphasize not making mistakes rather than the whole idea of not wanting. In most everyday situations, No quiero cometer errores is the natural choice.

Because cometer errores is the standard Spanish collocation.

Even though English uses make a mistake/error, Spanish most naturally says:

• cometer un error
• cometer errores

Spanish often does not match English word-for-word in these fixed combinations. So hacer errores sounds unnatural in standard Spanish.

The plural errores sounds more natural when talking about mistakes in general.

• No quiero cometer errores = I do not want to make mistakes
• No quiero cometer un error = I do not want to make one mistake / a mistake

Both are correct, but they mean slightly different things:

• plural = mistakes in general
• singular = one specific mistake, or the idea of making a mistake

This is a very common question because Spanish uses indicative and subjunctive differently after cuando.

Here, cuando hablo en público refers to something habitual or generally true:

• whenever I speak in public
• when I speak in public, in general

That is why hablo (present indicative) is used.

If you were talking about a specific future occasion, Spanish would often use the subjunctive:

• No quiero cometer errores cuando hable en público mañana.

So:

• cuando hablo = whenever I speak / when I speak generally
• cuando hable = when I speak on a future occasion

Because hablo here expresses a habitual situation, not an action happening right now.

• hablo en público = I speak in public / when I speak in public
• estoy hablando en público = I am speaking in public right now

Since the sentence is about a general situation, the simple present hablo is the natural form.

No. Spanish usually omits subject pronouns when the verb already makes the subject clear.

• No quiero cometer errores...
• Yo no quiero cometer errores...

Both are correct, but the version without yo is more natural unless you want emphasis or contrast.

For example:

• Yo no quiero cometer errores, pero él no se preocupa.

Here yo helps create contrast with él.

En público is the standard expression for in public.

So:

• hablar en público = to speak in public

This is a very common fixed phrase in Spanish.

You may also see públicamente, but that usually means publicly / openly, and it is not the normal choice for the activity of public speaking.

• hablar en público = speak before an audience
• decir algo públicamente = say something publicly

It usually means speaking before a group of people, especially in a formal or semi-formal setting.

For example:

• giving a presentation
• making a speech
• talking in front of a class
• addressing an audience

So it is not just talking outside or talking where other people can hear. It usually suggests public speaking as an activity.

Usually, errores is the better choice here.

Both words relate to mistakes, but error is much more common in this kind of sentence, especially with cometer.

• cometer errores = very natural
• cometer equivocaciones = understandable, but less common and less idiomatic here

A learner should strongly prefer cometer errores.

Yes, and it is very natural.

That version uses the reflexive verb equivocarse, which means to make a mistake / to be mistaken.

So you have two good options:

• No quiero cometer errores cuando hablo en público.
• No quiero equivocarme cuando hablo en público.

The meanings are very close. The first focuses on errors as things you make; the second focuses more on yourself making a mistake.

Cuando means when here and introduces a time clause.

The structure is:

• main clause: No quiero cometer errores
• time clause: cuando hablo en público

So the second part tells you when the main idea applies.

It is pronounced with the stress on the u syllable because of the written accent:

PÚ-bli-co

A few pronunciation notes for the full sentence:

• quiero: roughly KYE-ro
• cometer: stress on the last syllable, ko-me-TER
• hablo: the h is silent
• público: stress on the first syllable, PÚ-bli-co

That written accent in público is important because it tells you where the stress goes.

Yes, in many contexts you can.

• No quiero cometer errores cuando hablo en público.
• No quiero cometer errores al hablar en público.

Both are natural, but there is a slight nuance:

• cuando hablo en público = whenever I speak in public
• al hablar en público = when speaking in public / while speaking in public

The original sentence with cuando hablo sounds a bit more clearly habitual and personal. Both work well.