La livella è sul ponteggio.

La is the feminine singular definite article, meaning the.

It agrees with livella, which is a feminine singular noun:

• la livella = the level

In Italian, articles are used very often, so including la here is completely normal.

In Italian, nouns have grammatical gender. Livella is a feminine noun, so it takes la.

A lot of nouns ending in -a are feminine, although this is a pattern rather than an absolute rule. So:

• la livella
• not il livella

The adjective or article must agree with the noun’s gender and number.

È is the third-person singular of essere = to be.

So:

• la livella è = the level is

A very important detail: è has an accent.
This distinguishes it from e, which means and.

• è = is
• e = and

Because Italian usually contracts su + il into sul.

So:

• su + il = sul

Since ponteggio is a masculine singular noun that normally takes il, you get:

• il ponteggio
• sul ponteggio

This kind of contraction is very common in Italian.

Ponteggio is a masculine singular noun, so its article is il:

• il ponteggio

That is why, after su, it becomes:

• sul ponteggio

Many masculine singular nouns use il, especially those beginning with a normal consonant sound, as ponteggio does.

Usually sul ponteggio means on the scaffolding in a general location sense.

The preposition su often covers both:

• on
• onto
• sometimes the idea of on top of

If you want to be more explicitly above/on top of, Italian can also use sopra:

• sopra il ponteggio

But in many ordinary contexts, sul ponteggio is the most natural way to say it.

Yes, you could, but the nuance is slightly different.

• sul ponteggio = on the scaffolding
• sopra il ponteggio = above/on top of the scaffolding

In some situations they may sound very similar. However, su is often the more basic and idiomatic choice for physical location on a surface or structure.

This is the standard Italian sentence order:

• subject: La livella
• verb: è
• prepositional phrase of location: sul ponteggio

So it follows the very common pattern:

• [thing] + is + [place]

Italian can change word order for emphasis, but this neutral order is the most straightforward.

No, that would sound unnatural and incorrect in normal Italian.

Italian usually needs articles in cases like this:

• la livella
• il ponteggio
• sul ponteggio

English often drops articles where Italian keeps them, so this is something learners need to get used to.

A simple guide:

• livella ≈ lee-VEL-la
• ponteggio ≈ pon-TED-joh

A few details:

• In livella, the stress is on vel.
• In ponteggio, the gg before io sounds like the j in jam.
• The stress is on teg.

And è is pronounced like eh.

Sometimes yes, but è is the safest and most neutral choice here.

• La livella è sul ponteggio = standard, straightforward location
• La livella sta sul ponteggio = possible in spoken Italian, especially in some contexts, but less neutral

For simply identifying where an object is, essere is very common. Learners should definitely be comfortable with è first.

In everyday usage, livella commonly means a level, especially the tool used to check whether something is straight or horizontal.

Depending on context, Italian tool vocabulary can vary, but in a sentence like this, that is the natural interpretation. So a learner can safely understand la livella here as the tool.