Ci fermiamo non appena raggiungiamo la radura.

In fermarsi, the si shows that the verb is reflexive/pronominal: fermarsi = to stop / to stop oneself.

So:

• fermiamo = we stop something or we halt
• ci fermiamo = we stop / we stop ourselves

The pronoun changes with the subject:

• mi fermo = I stop
• ti fermi = you stop
• si ferma = he/she stops
• ci fermiamo = we stop
• vi fermate = you all stop
• si fermano = they stop

In this sentence, ci means ourselves, but in natural English we usually just say we stop.

Italian often uses the present tense to talk about the future, especially when the future event is:

• planned,
• expected,
• or clearly linked to a time expression or clause.

So Ci fermiamo non appena raggiungiamo la radura literally looks like:

• We stop as soon as we reach the clearing

But the intended meaning is often:

• We’ll stop as soon as we reach the clearing

This is very common in Italian. English can sometimes do something similar too:

• We stop when we get there
• We’ll stop when we get there

Italian is simply more comfortable using the present tense in these cases.

Non appena is a fixed expression meaning:

• as soon as
• the moment
• once

Here, non does not make the sentence negative. You should think of non appena as one unit.

Examples:

• Ti chiamo non appena arrivo. = I’ll call you as soon as I arrive.
• Partiamo non appena smette di piovere. = We leave as soon as it stops raining.

So in your sentence:

• Ci fermiamo non appena raggiungiamo la radura.
• We’ll stop as soon as we reach the clearing.

Yes. In many cases, appena and non appena can both mean as soon as.

So these are both possible:

• Ci fermiamo appena raggiungiamo la radura.
• Ci fermiamo non appena raggiungiamo la radura.

The version with non appena can sound a bit more formal, emphatic, or careful depending on context, but both are standard.

Be careful, though: appena can also mean just / barely / only just in other sentences.

For example:

• Ho appena mangiato. = I’ve just eaten.

So context matters.

After non appena, Italian normally uses the indicative, not the subjunctive, when you are talking about a real expected event.

So:

• non appena raggiungiamo = as soon as we reach

This is standard because the clause refers to something concrete and expected, not uncertain in the way that typically triggers the subjunctive.

Italian also often prefers the present indicative here even when English might use a future meaning.

So:

• quando arriviamo = when we arrive / when we get there
• non appena raggiungiamo = as soon as we reach

That is normal Italian grammar.

Both can relate to reaching a place, but they are not exactly the same.

• arrivare = to arrive
• raggiungere = to reach

Raggiungere usually emphasizes getting to a specific destination or point.

So:

• raggiungiamo la radura = we reach the clearing
• arriviamo alla radura = we arrive at the clearing

Notice the grammar difference too:

• raggiungere takes a direct object: raggiungere la radura
• arrivare usually uses a with a place: arrivare alla radura

Both could work in many contexts, but raggiungere la radura sounds a bit more like successfully getting to that exact spot.

In Italian, articles are used more often than in English, and with a noun like radura you normally need one.

So:

• la radura = the clearing

Without the article, radura would usually sound incomplete or unnatural here.

Italian generally wants an article before a singular countable noun in this kind of sentence, unless there is some special structure.

For example:

• vedo la casa = I see the house
• raggiungiamo la radura = we reach the clearing

The given word order is the most natural and neutral one:

• Ci fermiamo non appena raggiungiamo la radura.

Italian word order is fairly flexible, but not all versions sound equally natural.

Possible alternatives include:

• Non appena raggiungiamo la radura, ci fermiamo.

This means the same thing and may put slightly more emphasis on the as soon as clause.

In general:

• main clause first + time clause after it = very common
• time clause first + main clause after it = also very common

So both are correct.

A simple pronunciation guide is:

chee fehr-MYAH-mo non ap-PEN-na radd-joon-JAH-mo la ra-DOO-ra

A few helpful points:

• ci before f sounds like chee
• fermiamo has stress on -a-: fer-MIA-mo
• appena has stress on -pe-: ap-PEN-na
• raggiungiamo has a soft gi sound, roughly like j in English, and stress on -a-: rad-joon-JIA-mo
• radura has stress on -du-: ra-DU-ra

If you want to sound natural, try saying it in two rhythm groups:

• Ci fermiamo / non appena raggiungiamo la radura

Not by itself. Ci fermiamo is normally we stop or we’re stopping.

If you want let’s stop, Italian would usually say:

• Fermiamoci! = Let’s stop!

That is the first-person plural imperative of fermarsi.

So:

• Ci fermiamo non appena raggiungiamo la radura. = We’ll stop as soon as we reach the clearing.
• Fermiamoci non appena raggiungiamo la radura. = Let’s stop as soon as we reach the clearing.

A radura is a clearing, especially an open space in a forest or wooded area.

So the sentence suggests movement through nature, something like:

• walking through the woods,
• hiking,
• or traveling through a forested area.

It is a common and perfectly normal word, and it has a slightly descriptive, outdoors-related feel.