A veces dudo de mi pronunciación, pero sigo practicando español.

A veces is the fixed expression for sometimes in Spanish.

• a
  • veces = sometimes
• You normally learn it as one chunk.

So:

• A veces dudo... = Sometimes I doubt...

You would not normally say just Veces here.

Because dudar can be used in different ways, and in this sentence it means to doubt something / to have doubts about something.

Here:

• dudo de mi pronunciación = I doubt my pronunciation / I have doubts about my pronunciation

The de is very common after dudar when you are doubting a noun or thing.

Compare:

• Dudo de mi nivel. = I doubt my level.
• Dudo de eso. = I doubt that.

But you can also see:

• Dudo que sea fácil. = I doubt that it is easy.

So:

• dudar de + noun
• dudar que + clause

Because mi here is a possessive adjective meaning my.

• mi pronunciación = my pronunciation

mí with an accent is a pronoun meaning me, usually after a preposition:

• para mí = for me
• sin mí = without me

So in this sentence, mi has no accent because it means my.

The written accent shows where the stress falls: pronunciaCIÓN.

Without the accent, Spanish stress rules would make you read it differently. The accent is needed because the stress is on the last syllable.

Also, many nouns ending in -ción have this pattern:

• pronunciación
• conversación
• información
• situación

These are usually stressed on -ción.

In standard Peninsular Spanish, it is approximately:

pro-nun-thya-THYON

More carefully:

• pro = like pro
• nun = like noon but shorter
• cia = often like thya in much of Spain
• ción = thyon

A few useful points for Spain:

• ci is usually pronounced like th in thin
• the stress is on the last syllable: -ción

So the stress is here:

• pronunciaCIÓN

In Latin America, many speakers would pronounce ci with an s sound instead.

This is seguir + gerund, a very common structure meaning:

• to keep doing
• to continue doing

So:

• sigo practicando español = I keep practising Spanish / I continue practising Spanish

Breakdown:

• sigo = I continue / I keep going
• practicando = practising

More examples:

• Sigo aprendiendo. = I keep learning.
• Seguimos estudiando. = We continue studying.
• ¿Sigues trabajando? = Are you still working?

Yes, but the meaning changes a little.

• Practico español = I practise Spanish.
• Sigo practicando español = I keep practising Spanish / I’m still practising Spanish.

Sigo practicando emphasizes continuation. It suggests the action is ongoing, despite the doubt mentioned earlier.

That makes it fit very naturally with:

• pero = but

So the sentence has a nice contrast:

• I doubt my pronunciation, but I keep practising Spanish.

Because after seguir, Spanish often uses the gerund to show an ongoing action.

• seguir + gerund = keep doing / continue doing

So:

• seguir practicando = to keep practising

If you used the infinitive practicar, it would not fit this structure in the same way.

Correct:

• Sigo practicando.

Not natural here:

• Sigo practicar.

Because after verbs like hablar, estudiar, aprender, or practicar, languages are often used without an article.

So:

• practico español
• aprendo francés
• estudia inglés

That is normal Spanish.

You might see an article in other contexts, but here español as the object of practicando does not need one.

In Spanish, names of languages are normally written in lowercase.

So:

• español
• inglés
• francés

This is different from English, where you write Spanish, English, French with capital letters.

Both are in the present tense, first person singular:

• dudo = I doubt
• sigo = I continue / I keep on

The subject yo is not written because Spanish often leaves out subject pronouns when the verb ending already shows who the subject is.

So:

• (Yo) dudo
• (Yo) sigo

Both mean I because of the verb endings.

Because seguir is an irregular verb.

In the present tense, it changes like this:

• yo sigo
• tú sigues
• él/ella sigue
• nosotros seguimos
• vosotros seguís
• ellos/ellas siguen

Notice:

• e → i in most forms
• the yo form is sigo

So sigo practicando is the correct form for I keep practising.

Pero means but and creates a contrast between the two ideas:

• A veces dudo de mi pronunciación = sometimes I doubt my pronunciation
• pero sigo practicando español = but I keep practising Spanish

So the speaker is saying:

• there is doubt
• however, the action continues

It links the emotional difficulty with persistence.

Yes. Spanish word order is fairly flexible, although some versions sound more natural depending on emphasis.

Original:

• A veces dudo de mi pronunciación, pero sigo practicando español.

You could also say:

• Sigo practicando español, pero a veces dudo de mi pronunciación.

That changes the emphasis a bit:

• the original begins with the doubt
• the second begins with the perseverance

Both are grammatical.

Not exactly.

• pronunciación = pronunciation
• acento can mean accent

So:

• Dudo de mi pronunciación = I doubt how I pronounce words
• Dudo de mi acento = I doubt my accent / the way I sound as a speaker from another language background

They are related, but not identical. Pronunciación is broader and fits this sentence very well.