Leggo la destinazione sul tabellone.

Italian usually leaves out the subject pronoun when it is clear from the verb ending.
Leggo already means I read / I am reading, so io is not necessary.

You could say Io leggo la destinazione sul tabellone if you want extra emphasis, for example to contrast yourself with someone else.

Leggo is the first-person singular present indicative of leggere.

So it means:

• I read
• I am reading

Italian present tense often covers both the English simple present and present progressive, depending on context.

Italian uses articles more often than English. Here la destinazione refers to a specific destination, the one being read on the board.

So the definite article la is natural.

Compare:

• Leggo la destinazione = I read the destination
• Leggo una destinazione = I read a destination

The second one would sound less specific.

Because destinazione is the direct object of leggo.

The verb leggere takes a direct object directly:

• leggo il libro
• leggo il nome
• leggo la destinazione

So you do not say leggo alla destinazione in this meaning.

Sul means on the.

It is a contraction of:

• su = on
• il = the

So:

• su + il = sul

Because tabellone is masculine singular, sul is the correct form.

Because the information is thought of as being displayed on a surface.

So Italian says:

• sul tabellone = on the board

Using nel tabellone would usually suggest something physically inside the board, which is not the idea here.

Tabellone usually means a large board, display board, or notice board.

In travel contexts, it often refers to something like:

• a departures board
• an arrivals board
• an information display

It comes from tabella, and the ending -one often gives the idea of something larger. So tabellone is basically a big board/display.

Yes, depending on how you translate naturally.

Literally, sul tabellone is on the board, but in English you might sometimes say from the board if you are emphasizing the source of the information.

Italian is focusing on where the destination is written or shown: on the board.

Yes. Italian word order is more flexible than English.

The sentence as given, Leggo la destinazione sul tabellone, is a neutral, natural order.

You could also say:

• Sul tabellone leggo la destinazione

This puts more emphasis on where you are reading it.

The original version is the most straightforward one for everyday use.

Leggo is pronounced approximately LEHD-joh, or in IPA /ˈleddʒo/.

A few useful points:

• e is like the e in bed
• gg here sounds like the j sound in judge, but stronger
• the stress is on the first syllable: LEG-go

So it is not pronounced like English lego.

It can mean either, depending on context.

In Italian, the present tense often does the work of both:

• I read the destination on the board
• I am reading the destination on the board

If you want to strongly emphasize the ongoing action, Italian can also use sto leggendo, but the simple present is very common.

Yes. You can replace it with la:

• La leggo sul tabellone.

Here la means it, referring to la destinazione.

Notice that in Italian object pronouns usually go before the conjugated verb:

• leggo la destinazione
• la leggo

Yes. It is masculine singular:

• il tabellone

That is why you get:

• sul tabellone = su + il tabellone

If it were feminine singular, the contraction would be different, for example:

• sulla tabella = su + la tabella