Learn Hardcore Malay: Saya kerap membaca buku sejarah di perpustakaan. - I often read history books in the library.

kerap – often, frequently (quite neutral; common in more careful / standard Malay).
sering – also means often; very common, especially in Indonesian and also understood in Malay.
selalu – literally always, but in everyday Malaysian speech it can sometimes feel like often. In careful / formal usage, it is closer to always.

In your sentence, Saya kerap membaca… = I often read…
You could also say:

Saya sering membaca buku sejarah di perpustakaan.
Saya selalu membaca buku sejarah di perpustakaan. (more like I always read… in standard usage)

Why is kerap placed after Saya and before membaca? Can it move to other positions?

The normal place for frequency adverbs like kerap is after the subject and before the main verb:

Saya kerap membaca… – I often read…

Other possible positions:

Fronted for emphasis:
- Kerap saya membaca buku sejarah di perpustakaan.
  Emphasises how often more strongly: Often, I read history books at the library.
After the verb (less common / more marked):
- Saya membaca kerap buku sejarah… – sounds awkward or wrong in standard Malay.

So, for everyday, natural Malay, put kerap right before the verb:
Saya kerap membaca…

Why is there no separate word for am or do (like in “I often read”) – how does tense work here?

Malay verbs do not change form for tense (past, present, future) the way English verbs do, and there is no separate am/do helper.

Saya kerap membaca buku sejarah di perpustakaan can mean:

I often read history books at the library. (present habit)
I often read history books at the library (in the past). (past habit, if context is past)

Tense and time are usually shown by:

Time words: semalam (yesterday), tadi (earlier), nanti (later), esok (tomorrow), setiap hari (every day), etc.
Context, or explicitly saying dulu (used to), akan (will), etc.

Example:

Dulu saya kerap membaca buku sejarah di perpustakaan.
= I used to often read history books at the library.

What is the difference between baca and membaca? Why does the sentence use membaca?

The root verb is baca (to read).
Membaca is formed with the meN- verb prefix:

meN- + baca → membaca

Differences:

membaca – more formal / standard, often used in writing, careful speech, or when the verb stands alone as a neutral infinitive-like form.
baca – root form; very common in informal speech and in imperatives.

In your sentence:

Saya kerap membaca buku sejarah di perpustakaan. (more standard)
Saya kerap baca buku sejarah di perpustakaan. (perfectly fine in everyday speech; a bit more casual)

Both are grammatical; membaca just sounds a bit more formal/complete.

Why is it buku sejarah and not sejarah buku for “history book(s)”?

In Malay, when one noun modifies another, the main noun comes first, and the describing noun comes after.

buku = book
sejarah = history
buku sejarah = a book about history → history book

So the pattern is:

[main noun] + [describing noun]

Other examples:

baju tidur – sleep clothes → pyjamas
guru bahasa – language teacher
kereta polis – police car

Sejarah buku would mean the history of the book, a different idea.

Does buku sejarah mean one book or many books? How do you show plural?

Buku sejarah on its own is number-neutral:

It can mean a history book, the history book, or history books, depending on context.

Malay usually does not mark plural on nouns. To make plural explicit, you can:

Use a number or quantity word:
dua buku sejarah – two history books
banyak buku sejarah – many history books
Use reduplication (more formal / emphatic):
buku-buku sejarah – history books (plural, emphatic)

In everyday sentences, buku sejarah is enough, and listeners infer singular vs plural from context.

Why is di used in di perpustakaan? What is the difference between di and ke?

Di marks a location (at / in / on) where something is, not movement:

di perpustakaan – at the library / in the library

Ke marks movement towards a place (to):

Saya pergi ke perpustakaan. – I go to the library.

In your sentence, the action (reading) happens at the library, so we use di, not ke:

Saya kerap membaca buku sejarah di perpustakaan.
= I often read history books at the library.

Could I say di dalam perpustakaan instead of di perpustakaan? Is there a difference?

Yes, you can say both:

di perpustakaan – at the library / in the library (general; most common)
di dalam perpustakaan – literally inside the library, slightly more explicit.

Most of the time, di perpustakaan is enough and sounds more natural unless you really want to stress “inside” (for contrast, e.g. not outside the building).

Can I leave out Saya and just say Kerap membaca buku sejarah di perpustakaan?

Yes, that is possible in the right context.

Malay can omit the subject pronoun when it is clear from context who is being talked about. So:

Kerap membaca buku sejarah di perpustakaan.
could mean (I/you/he/she) often read history books at the library.

However:

In formal writing or when the subject might be unclear, it is safer to keep Saya.
In spoken conversation, dropping Saya is common when continuing a topic already understood.

For a standalone sentence in a textbook, Saya kerap… is clearer.

Why is there no word like the or a in the sentence?

Malay has no direct equivalent of English articles a/an and the.

So buku sejarah can correspond to:

a history book
the history book
history books

Which English article you use depends on context in English, not on any extra word in Malay.

If you need to be very specific, you use other devices, for example:

buku sejarah itu – that history book / the history book (known, specific)
sebuah buku sejarah – a (single) history book

But generally, Malay leaves this implicit.

What does perpustakaan literally mean? Is it related to any other word?

Perpustakaan means library.

It is built from the older word pustaka (from Sanskrit, meaning book / writings / literature) plus the circumfix per-…-an, which often makes a place noun:

pustaka – book, writings, literature
perpustakaan – place of books / literature → library

You’ll see pustaka in some names, for example:

Dewan Bahasa dan Pustaka – a major language and literature body in Malaysia

For everyday vocabulary, just remember perpustakaan = library.

What is the difference between perpustakaan and kedai buku?

perpustakaan – library, a place where you borrow or read books.
kedai buku – bookshop / bookstore, a place where you buy books.
(kedai = shop, buku = book)

So your sentence:

Saya kerap membaca buku sejarah di perpustakaan.
clearly means you read in a library, not in a bookshop.

Is Saya always the right word for I, or can I use Aku here?

Both Saya and Aku mean I, but they differ in politeness and context:

Saya – polite, neutral, used with strangers, elders, in formal situations, writing, etc.
Aku – more intimate / casual, used with close friends, family, in songs, prayers, etc.

Your sentence uses Saya, which is the safe, polite choice:

Saya kerap membaca buku sejarah di perpustakaan.

With Aku, it becomes:

Aku kerap membaca buku sejarah di perpustakaan.

Grammatically fine, but the tone is more personal / informal and depends on your relationship with the listener.

Can I add a time expression like setiap hari? Where would it go?

Yes, you can add time expressions such as setiap hari (every day), pada waktu malam (at night), etc.

Common and natural placements:

After the subject, before kerap:
- Saya setiap hari kerap membaca buku sejarah di perpustakaan.
  (emphasis that it’s every day)
At the end:
- Saya kerap membaca buku sejarah di perpustakaan setiap hari.
At the beginning:
- Setiap hari, saya kerap membaca buku sejarah di perpustakaan.

All are grammatical; small differences are in emphasis and style, not grammar.