Riempio la borraccia al ruscello.

Riempio is the 1st person singular present indicative of riempire.

So it means I fill or, depending on context, I am filling.

Italian present tense is often a bit broader than English:

• Riempio la borraccia al ruscello can mean I fill my water bottle at the stream as a habit
• or I’m filling the water bottle at the stream right now

The verb ending -o tells you the subject is I.

Because Italian often leaves subject pronouns out when they are already clear from the verb.

• Riempio already means I fill / I am filling
• so io is not necessary

You could say Io riempio la borraccia al ruscello, but that usually adds emphasis, such as:

• I fill the bottle at the stream
• not someone else

This is very normal in Italian.

Because riempire does not follow the -isc- pattern.

Some -ire verbs do this:

• capire → capisco
• finire → finisco

But riempire is different:

• io riempio
• tu riempi
• lui/lei riempie
• noi riempiamo
• voi riempite
• loro riempiono

So riempisco is not correct for this verb.

Borraccia is a feminine singular noun, so its definite article is la.

• la borraccia = the water bottle / the canteen
• una borraccia = a water bottle / a canteen

In this sentence, la suggests a specific bottle, probably the speaker’s bottle or one already known in context.

Italian often uses the definite article in places where English might sometimes use my or no article at all, depending on context.

Because riempire takes a direct object.

So:

• riempio la borraccia = I fill the water bottle

There is no a, di, or other preposition before the thing being filled.

If you want to say what you fill it with, Italian can add that separately:

• Riempio la borraccia d’acqua = I fill the bottle with water
• Riempio la borraccia con l’acqua del ruscello = I fill the bottle with the stream’s water

So la borraccia is the object being filled.

Al ruscello means at the stream or by the stream.

It tells you the place where the action happens.

So the sentence is not mainly emphasizing the source of the water, but the location:

• Riempio la borraccia al ruscello = I fill the bottle at the stream

If you wanted to emphasize the water coming from the stream, you might say something like:

• Riempio la borraccia con l’acqua del ruscello
• Riempio la borraccia dal ruscello in some contexts, though the first option is often clearer

In the original sentence, al ruscello is best understood as a place phrase.

Because in Italian, a + il contracts to al.

This is one of the standard preposition + article combinations:

• a + il = al
• a + lo = allo
• a + la = alla
• a + i = ai
• a + gli = agli
• a + le = alle

So:

• al ruscello = a il ruscello

The contracted form is the normal one.

Because Italian usually uses an article with common nouns after prepositions when referring to a specific place.

So Italian says:

• al ruscello not normally
• a ruscello

This is very common:

• al mare = at the sea
• al parco = at the park
• al fiume = at the river
• al ruscello = at the stream

English often uses no article in some expressions, but Italian usually does.

Yes. Italian word order is more flexible than English word order.

The neutral order here is:

• Riempio la borraccia al ruscello

But other orders are possible for emphasis:

• Al ruscello riempio la borraccia = At the stream, I fill the bottle
• La borraccia la riempio al ruscello = The bottle, I fill it at the stream

The original sentence is the most straightforward and neutral version.

It is pronounced roughly roo-SHEL-lo.

A few useful points:

• sc before e or i sounds like English sh
• so ruscello has she, not ske
• the stress is on -scel-

So:

• ru-scèl-lo

Also, the double ll is pronounced more distinctly than a single consonant, though learners do not need to exaggerate it too much at first.