Tarikh akhir ialah hari Isnin.

In Malay, the main noun usually comes first, and words that describe or limit it usually come after it.

So:

• tarikh = date
• akhir = final / end

Together, tarikh akhir literally means final date, which is the natural Malay order.

This is very common in Malay:

• kereta merah = red car
• rumah besar = big house
• tarikh akhir = final date / deadline

So the word order is different from English, but completely normal in Malay.

Ialah is a linking word, roughly like is / equals / is defined as in English.

In this sentence, it links:

• Tarikh akhir = the subject
• hari Isnin = the thing it is being identified as

So:

• Tarikh akhir ialah hari Isnin.
  = The deadline is Monday.

In standard Malay, ialah is often used when the thing after it is a noun phrase.

Yes, very often you can, especially in casual speech or short written notices.

So you may also hear:

• Tarikh akhir hari Isnin.

That sounds shorter and more conversational.

However, Tarikh akhir ialah hari Isnin sounds clearer, more complete, and more formal/standard, so it is very suitable for writing, announcements, or teaching examples.

This is a very common learner question.

In traditional standard grammar:

• ialah is used before a noun phrase
• adalah is used before an adjective phrase or prepositional phrase

Here, hari Isnin is a noun phrase, so ialah is the expected choice:

• Tarikh akhir ialah hari Isnin.

Compare:

• Mesyuarat itu adalah penting.
  (penting = important, an adjective)

• Mesyuarat itu adalah pada hari Isnin.
  (pada hari Isnin = on Monday, a prepositional phrase)

In everyday usage, some speakers mix ialah and adalah, but if you want the standard textbook rule, ialah is the better choice here.

Hari Isnin literally means Monday day, but in Malay this is a normal way to name a day of the week.

• hari = day
• Isnin = Monday

Malay often uses hari with weekdays:

• hari Isnin = Monday
• hari Selasa = Tuesday
• hari Jumaat = Friday

In many contexts, Isnin by itself is also understandable, but hari Isnin sounds a bit fuller and more explicit.

So this sentence is perfectly natural as written.

Because Malay does not use articles like a, an, and the the way English does.

So Malay can simply say:

• Tarikh akhir ialah hari Isnin.

and the listener understands from context that it means something like:

• The deadline is Monday.

Malay usually leaves definiteness to context, rather than marking it with a separate word.

In this kind of sentence, Malay does not need a separate word for on.

English often says:

• The deadline is Monday
• The deadline is on Monday

Malay can simply say:

• Tarikh akhir ialah hari Isnin.

If you want to include the idea of on, Malay often uses pada:

• Tarikh akhir adalah pada hari Isnin.

That version is also possible, but it is structured differently:

• ialah hari Isnin = is Monday
• adalah pada hari Isnin = is on Monday

So in the original sentence, nothing is missing; it is just a different Malay structure.

Yes. Tarikh akhir is a very common and natural way to mean deadline, especially in formal or practical contexts such as:

• assignments
• application forms
• registrations
• payments
• official notices

Literally it means final date, which matches the idea of a deadline very well.

Depending on context, you may also see other expressions, but tarikh akhir is one of the most common and useful ones to learn.

Yes, it sounds standard and slightly formal, but still very natural.

It would fit well in:

• school instructions
• office notices
• emails
• forms
• announcements

A more casual or shortened version might be:

• Tarikh akhir hari Isnin.

And in very informal mixed speech, some people might even say:

• Deadline hari Isnin.

But if you want a good, correct, standard Malay sentence, Tarikh akhir ialah hari Isnin. is an excellent model.