Learn Hardcore Italian: Arrivo presto, cioè alle otto in punto. - I arrive early, that is, at eight o’clock sharp.

Common near-synonyms: ossia, vale a dire (more formal/neutral).
In conversation, cioè can also act as a filler like I mean; don’t overuse it in writing.

Why is there a comma before cioè?

Because cioè starts an explanatory aside. Italian typically sets it off with a comma; if it were in the middle of a sentence, you’d usually have commas on both sides. You can also use other punctuation to introduce the clarification:

Arrivo presto: alle otto in punto.
Arrivo presto (cioè alle otto in punto).

Why is it Arrivo and not Io arrivo?

Italian normally drops subject pronouns because the verb ending shows the person. Arrivo already tells you it’s I. You add io mainly for emphasis or contrast:

Io arrivo presto, ma tu no.

Why use the present tense Arrivo if the arrival is in the future?

Italian often uses the simple present for near-certain or scheduled future events, especially with a time expression. Alternatives:

Present: Arrivo alle otto in punto.
Future: Arriverò alle otto in punto (a bit more formal/distant).
Periphrastic: Sto per arrivare (I’m about to arrive).

Does presto mean early or soon?

Both are possible, depending on context.

With arrivals/appointments, arrivare presto normally means arrive early.
For soon in the sense of shortly, prefer tra poco, a breve: Arrivo tra poco. The clause with cioè here removes ambiguity by giving the exact time.

Can presto also mean quickly/fast?

Sometimes, yes, in set phrases like Fai presto! (Hurry up!). But with movement verbs, quickly is more naturally in fretta or rapidamente:

Early: Sono arrivato presto.
Quickly: Sono arrivato in fretta.

Why is it alle otto and not a otto?

Time expressions take the articulated preposition: a + le = alle because hours are treated as feminine plural (understood: le ore).

1: all’una (a + l’).
2, 3, …: alle due, alle tre …
Special cases: a mezzogiorno, a mezzanotte (no article).

What does in punto add to the meaning?

In punto means exactly on the dot, sharp. Synonyms:

alle otto precise / esatte (neutral)
alle otto spaccate (colloquial)

What if I drop in punto?

Alle otto simply means at eight, without emphasizing exactness. In punto adds the idea of punctual precision.

Can I move presto to another position?

The neutral spot is after the verb: Arrivo presto. Fronting it (Presto arrivo) is possible but sounds marked or literary. You can also put the time first: Alle otto in punto arrivo.

How do I pronounce cioè, and is the accent required?

Pronunciation: roughly cho-EH, with the stress on è (open “eh” sound).
The accent in cioè is mandatory in writing. Without it (cioe) is wrong. Pronunciation tips: Arrivo has a rolled/trilled r; otto has a double t; in in punto, the n often assimilates to a [m] sound before p (im punto).

Could I use other words instead of cioè?

Yes:

ossia, vale a dire: that is, namely (more formal/neutral).
ovvero: in contemporary usage it often means or rather/that is in formal writing, but it can also mean or; to avoid ambiguity in everyday speech, stick with cioè.

How do I say by eight or around eight?

By eight (deadline): entro le otto or per le otto (the latter is common in speech).
Around/about eight: verso le otto, intorno alle otto.
No later than eight, exactly: alle otto in punto.

Is a presto related to presto here?

They share the word presto, but A presto! is a fixed phrase meaning See you soon! You wouldn’t say arrivo a presto. Use arrivo presto or arrivo tra poco.

Why is le used with hours? Why feminine plural?

Italian conceptualizes clock hours as plural feminine because the understood noun is le ore (the hours). Hence:

Sono le otto. Arrivo alle otto.
Exception: one o’clock is singular feminine: È l’una. Arrivo all’una.