Saya membaca email reservasi itu lagi sebelum check-in.

Membaca is the usual active verb form in standard Indonesian. It comes from the root baca (to read) plus the prefix meN-, which becomes mem- here.

So:

• baca = root/base form
• membaca = to read / read(s) in a normal sentence

In careful or neutral Indonesian, if you say Saya membaca email..., that sounds complete and natural.

You may also hear Saya baca email... in conversation. That is common in informal speech, but membaca is more standard.

No. Indonesian verbs usually do not change for tense the way English verbs do.

So Saya membaca email reservasi itu lagi could mean:

• I read that reservation email again
• I am reading that reservation email again
• I will read that reservation email again

The time is understood from context, or from time words such as:

• kemarin = yesterday
• sekarang = now
• besok = tomorrow

In this sentence, sebelum check-in helps give a time relationship, but membaca itself does not mark tense.

Here itu works like that or sometimes the, depending on context.

In Indonesian, words like ini (this) and itu (that) usually come after the noun:

• email itu = that email
• rumah itu = that house

In your sentence, it follows the whole noun phrase:

• email reservasi itu = that reservation email

Very often, itu does not sound strongly like English that. It can simply make the noun more specific, closer to the in English.

Indonesian usually puts the main noun first, followed by words that describe or specify it.

So:

• email reservasi = literally email reservation, but naturally understood as reservation email
• hotel mewah = luxury hotel
• tiket pesawat = plane ticket

The first noun is the head noun, and the second noun modifies it.

So email reservasi means an email related to the reservation.

Here lagi means again.

So:

• membaca ... lagi = read ... again

Examples:

• Saya coba lagi. = I’ll try again.
• Tolong jelaskan lagi. = Please explain again.

Be careful: lagi can sometimes also be part of other meanings in different contexts, such as ongoing action in informal speech with sedang/lagi, but in this sentence it clearly means again.

That placement is natural in Indonesian. Lagi often comes after the object or near the end of the verb phrase.

So this is natural:

• Saya membaca email reservasi itu lagi.

You may also hear slight variations in speech, but the given version is very normal.

A useful pattern is:

• Subject + verb + object + lagi

For example:

• Saya menonton film itu lagi. = I watched that movie again.
• Dia membaca pesan saya lagi. = He/She read my message again.

Because the subject is already clear.

Sebelum means before, and after it Indonesian often allows a shorter phrase when the meaning is obvious.

So:

• sebelum check-in = before checking in
• sebelum saya check-in = before I checked in / before I check in

Both can work, but the shorter version is very natural when the person doing the action is understood to be the same person as in the main clause.

This is similar to English using before checking in instead of always saying before I checked in.

It is a common loanword, especially in travel, hotels, and airports.

Modern Indonesian often uses English-derived words in certain situations, especially for:

• travel
• business
• technology
• online communication

So check-in is widely understood. Depending on context, speakers might also use more Indonesian alternatives, but check-in is common and natural.

The same is true for email.

Yes. That is common in everyday speech.

Compare:

• Saya membaca email reservasi itu lagi sebelum check-in. = more standard / neutral
• Saya baca email reservasi itu lagi sebelum check-in. = more informal / conversational

Both are understandable and natural. If you are learning standard written Indonesian, membaca is the safer form to learn first.

Indonesian does not have articles like English a/an/the.

Whether something is definite or indefinite is usually understood from context, or shown in other ways, such as with:

• itu = that / the specific one
• ini = this
• context alone

So email reservasi itu can convey something like that reservation email or the reservation email, even though Indonesian does not use a separate word exactly like English the.

Email is much more common in everyday use.

You may see surel as a recommended or more formal Indonesian equivalent, but in real life many people simply say:

• email
• kirim email
• cek email

So for most practical purposes, email is the word you will hear most often.

Yes, it is natural and clear.

It has a very typical structure:

• Saya = subject
• membaca = verb
• email reservasi itu = object
• lagi = again
• sebelum check-in = time phrase

A native speaker would understand it easily. The main thing to notice is that it mixes standard Indonesian with common loanwords (email, check-in), which is very normal in modern usage.