Ŝi bedaŭris, ke ŝi parolis tro forte al la kelnerino.

In this sentence, repeating ŝi is normal and clear Esperanto:

Ŝi bedaŭris, ke ŝi parolis tro forte al la kelnerino.

After ke (that), a new clause begins, and that clause normally has its own subject. So Esperanto usually says ke ŝi parolis, not just ke parolis.

Leaving out the second ŝi would sound incomplete or unnatural in standard Esperanto.

Bedaŭri means to regret or to be sorry about.

The ending -is marks the past tense in Esperanto, so bedaŭris means regretted or was sorry.

A quick comparison:

• bedaŭras = regrets / is sorry
• bedaŭris = regretted / was sorry
• bedaŭros = will regret

So Ŝi bedaŭris means that her regret happened in the past.

Ke means that and introduces a subordinate clause.

So:

• Ŝi bedaŭris = She regretted / She was sorry
• ke ŝi parolis tro forte al la kelnerino = that she spoke too loudly to the waitress

It works very much like English that in sentences such as:

• She said that...
• He knew that...
• They regretted that...

In Esperanto, ke is very commonly used in this kind of structure.

Parolis is the simple past of paroli, meaning to speak.

So ŝi parolis tro forte means she spoke too loudly.

Why not other verbs?

• diris means said. That focuses more on what was said.
• parolis focuses on the act or manner of speaking.
• paroladis suggests repeated or ongoing speaking, something like was going on speaking or spoke for a while.

Here, parolis is the most neutral and natural choice.

Yes. Forta is an adjective meaning strong.

But here we need an adverb, because it describes the verb parolis—that is, how she spoke. Adverbs in Esperanto end in -e, so:

• forta = strong
• forte = strongly / loudly

In this sentence, tro forte means something like too loudly or too forcefully.

So the logic is:

• adjective (-a) describes a noun
• adverb (-e) describes a verb, adjective, or another adverb

Yes, depending on context.

Literally, forte means strongly. When used with speaking, it can suggest:

• too loudly
• too forcefully
• too harshly

So ŝi parolis tro forte al la kelnerino can mean that her speech was excessive in force, volume, or intensity.

If the context is mainly about volume, English might say too loudly. If the context is more about tone, English might say too harshly or too sharply.

Because al already shows direction or recipient: to.

So:

• al la kelnerino = to the waitress

The accusative -n is not used here because kelnerino is not the direct object of the verb parolis. She is the person spoken to, not the thing spoken.

Compare:

• Ŝi vidis la kelnerinon. = She saw the waitress.
  Here la kelnerinon is a direct object, so it takes -n.
• Ŝi parolis al la kelnerino. = She spoke to the waitress.
  Here al marks the relationship, so no -n is needed.

Kelnerino means waitress.

It is built from:

• kelner- = waiter/server
• -in- = female
• -o = noun ending

So:

• kelnero = waiter / server
• kelnerino = waitress

This is a very common Esperanto pattern:

• patro = father
• patrino = mother
• frato = brother
• fratino = sister

The given word order is the most neutral and natural:

Ŝi bedaŭris, ke ŝi parolis tro forte al la kelnerino.

Esperanto word order is fairly flexible, but not completely free. You can move things for emphasis, but the basic structure here is very standard.

For example, these are possible, though less neutral:

• Ŝi bedaŭris, ke al la kelnerino ŝi parolis tro forte.
• Ke ŝi parolis tro forte al la kelnerino, ŝi bedaŭris.

A learner should usually stick with the original order unless there is a reason to emphasize something.

In Esperanto, a comma is normally used before a subordinate clause introduced by words like ke, ĉar, kvankam, and similar conjunctions.

So:

• Ŝi bedaŭris, ke...

This comma is standard punctuation in Esperanto.

English punctuation can be more flexible with that, but Esperanto more regularly marks the clause boundary with a comma.

Yes. Tro laŭte would also be very natural, and in some contexts it may be even more specifically too loudly.

The difference is roughly this:

• laŭte = loudly
• forte = strongly, forcefully, sometimes loudly depending on context

So:

• paroli tro laŭte emphasizes volume
• paroli tro forte can emphasize volume, force, or harsh intensity

Both are possible, but they are not always exactly identical in nuance.

Esperanto does not have a complicated tense sequence system like English sometimes does. It usually uses the tense that directly matches the time of each action.

Here:

• bedaŭris = her regret was in the past
• parolis = her speaking was also in the past

That is straightforward and normal Esperanto.

English often does the same:

• She regretted that she spoke too loudly...

Depending on style, English might also say:

• She regretted that she had spoken too loudly...

Esperanto could use a more explicit earlier-past form if needed, but the simple past is usually enough when the meaning is clear.

Here is the structure:

• Ŝi = she
• bedaŭris = regretted / was sorry
• ke = that
• ŝi = she
• parolis = spoke
• tro = too
• forte = loudly / forcefully
• al = to
• la = the
• kelnerino = waitress

So the sentence has:

1. a main clause: Ŝi bedaŭris
2. a subordinate clause introduced by ke: ke ŝi parolis tro forte al la kelnerino

That is a very common Esperanto sentence pattern.