Parliamo seriamente del problema.

Parliamo is the 1st person plural form of parlare in the present tense.

It can mean either:

• we speak / we are speaking
• let’s speak / let’s talk

In a sentence like Parliamo seriamente del problema, context usually tells you which one is meant.

Very often, a plain present-tense noi form is used in Italian as a suggestion or invitation, so it can sound like:

• Let’s talk seriously about the problem.

That use is sometimes called the hortatory use of the present tense.

Italian often drops subject pronouns when they are not needed, because the verb ending already shows who the subject is.

• parlo = I speak
• parli = you speak
• parla = he/she speaks
• parliamo = we speak
• parlate = you all speak
• parlano = they speak

So parliamo already clearly means we.
You could say Noi parliamo seriamente del problema, but adding noi usually gives extra emphasis or contrast, such as:

• Noi parliamo seriamente del problema, non loro.

Seriamente is an adverb. It comes from the adjective serio (serious).

Italian often forms adverbs from adjectives by using -mente, similar to English -ly:

• serio → seriamente = seriously
• chiaro → chiaramente = clearly
• rapido → rapidamente = quickly

Here, seriamente describes how the talking is done: in a serious way.

Because in Italian, the preposition di combines with the definite article il:

• di + il = del

This kind of contraction is extremely common and is called a preposizione articolata.

Some other common combinations are:

• di + lo = dello
• di + la = della
• di + i = dei
• di + gli = degli
• di + le = delle

So:

• del problema = of the problem / about the problem

The verb parlare is commonly used with di to mean to talk about something.

So:

• parlare di qualcosa = to talk about something

Examples:

• Parliamo di politica.
• Parlo di te.
• Abbiamo parlato del film.

This is just the normal pattern to learn with the verb.

Sometimes yes, but not always with exactly the same feel.

• parlare di = the most common, neutral way to say talk about
• parlare su is generally not standard in this sense
• parlare di and sometimes parlare del/sul tema argomento may overlap depending on context, but parlare di is the safest and most natural choice here

You may also see discutere di or discutere il problema, depending on what you want to express. But for this sentence, parlare del problema is completely normal.

In Italian, abstract or specific nouns often take the definite article where English may not.

Here, il problema usually means the problem, referring to a specific issue already known in context.

So:

• del problema = about the problem

Saying di problema would generally sound wrong here.

Italian uses articles more often than English, so this is something learners have to get used to.

Yes. Italian adverbs can often move around, although some positions sound more natural than others.

These are possible:

• Parliamo seriamente del problema.
• Parliamo del problema seriamente.
• Seriamente, parliamo del problema.

The first one is the most neutral and natural in many contexts.

Changing the position can slightly change the emphasis:

• Parliamo seriamente del problema focuses smoothly on the manner of talking.
• Seriamente, parliamo del problema can sound like Seriously, let’s talk about the problem.

Yes, problema is masculine, even though it ends in -a.

That is why the sentence has:

• il problema
• del problema

This happens with some Italian nouns of Greek origin, especially words ending in -ma, such as:

• il problema
• il sistema
• il tema
• il programma

So the ending -a does not always mean a noun is feminine.

It is pronounced roughly par-LYAH-mo.

A few helpful points:

• the gli sound is not present here; it is just li-a
• stress falls on -a- in -lià-: parliàmo
• the r is tapped or rolled in standard Italian pronunciation

So say it as three parts:

• par
• lià
• mo

It is basically neutral. Nothing in it is especially formal or especially casual.

• Parliamo seriamente del problema. can work in everyday conversation, at work, or in a discussion.
• It sounds direct, clear, and natural.

If you wanted something more formal, you might choose a different verb or phrasing, such as:

• Discutiamo seriamente il problema.
• Affrontiamo seriamente il problema.

But the original sentence is perfectly normal and not inappropriate in standard speech.

They are related, but not identical.

• parlare del problema = to talk about the problem
• discutere il problema / discutere del problema = to discuss the problem
• affrontare il problema = to tackle/address the problem

So Parliamo seriamente del problema suggests opening or having a serious conversation about it. It does not necessarily imply solving it yet.

If you want a stronger sense of action, affrontare is often better.

Yes, in context it can.

Because parliamo can have a let’s... meaning, the sentence may function like a suggestion, prompt, or mild command:

• Let’s talk seriously about the problem.

It is not a command to you alone. It includes the speaker too, so it is more like a shared proposal.

That is one reason this form is very common in conversation: it can sound cooperative rather than bossy.