Il piano può fallire.

In Italian, singular countable nouns usually need an article when you are talking about a specific thing in a normal statement.

So il piano = the plan.

Leaving out the article would usually sound incomplete here. Italian uses articles more often than English does.

Yes. Piano can mean different things depending on context.

In this sentence, il piano means the plan.

Very common meanings of piano include:

• plan
• floor/storey of a building
• soft/quiet in music
• the shortened form of pianoforte in some contexts

So this is a good example of why context matters.

The accent is part of the correct spelling of this form.

Può is the he/she/it and you (formal) form of potere in the present tense:

• io posso
• tu puoi
• lui/lei può
• noi possiamo
• voi potete
• loro possono

The accent marks the stressed vowel and helps distinguish the form in writing.

Può is a modal verb, from potere, meaning can / may / to be able to.

When Italian uses a modal verb, it is normally followed by an infinitive:

• può fallire = can fail / may fail

So:

• può = finite verb
• fallire = infinitive

This is very similar to English can fail.

Because it comes after the modal verb potere.

After potere, dovere, and volere, Italian usually uses the infinitive:

• può fallire = can fail
• deve partire = must leave
• vuole mangiare = wants to eat

So fallire stays in the base infinitive form.

Mostly yes. Fallire is an -ire verb.

Its infinitive is fallire = to fail.

Some present-tense forms are:

• io fallisco
• tu fallisci
• lui/lei fallisce
• noi falliamo
• voi fallite
• loro falliscono

So it behaves like many -ire verbs that add -isc- in some forms.

It can mean either, depending on context.

In many cases, può fallire expresses possibility:

• The plan can fail
• The plan may fail

English chooses between can and may depending on style and nuance, but Italian often uses potere for both kinds of possibility.

Yes, but it means something slightly different.

• Il piano può fallire = the plan can fail
  This usually refers to a specific plan already known in the conversation.

• Un piano può fallire = a plan can fail
  This is more general, like a general statement or principle.

So the article changes whether you are talking about a specific plan or plans in general.

Può is pronounced roughly like pwo in English, as one syllable with a glide at the start.

A simple approximation is:

• può ≈ pwo

The stress is on that only syllable.

Fallire is pronounced approximately:

• fal-LEE-reh

The stress is on -li-.

So the whole sentence sounds roughly like:

• eel PYAH-no pwo fal-LEE-reh

That is only an approximation, but it is a useful starting point.

Yes, but Il piano può fallire is the normal, neutral order.

Italian usually follows a basic subject + verb pattern here:

• Il piano = subject
• può fallire = verb phrase

You might change the order for emphasis in special contexts, but for learners, this sentence is the standard way to say it.

No. Fallire is used for many kinds of failure, such as:

• Il piano fallisce = The plan fails
• L’impresa è fallita = The business went bankrupt / failed
• Ha fallito l’esame = He/She failed the exam

So it can refer to:

• plans failing
• people failing at something
• businesses failing
• attempts failing

The exact meaning depends on context.