Die verlies is ernstig.

Because Die verlies is ernstig uses ernstig as a predicate adjective: it comes after is and describes the subject.

• Die verlies is ernstig = The loss is serious
• die ernstige verlies = the serious loss

So both are possible, but they mean slightly different things grammatically:

• Die verlies is ernstig = a full sentence
• die ernstige verlies = just a noun phrase, not a complete sentence by itself

Notice that the adjective changes form when it comes before the noun:

• after is: ernstig
• before the noun: ernstige

Word by word:

• Die = the
• verlies = loss
• is = is
• ernstig = serious

So the structure is very close to English:

• Die verlies = the loss
• is ernstig = is serious

Here, die is the definite article, so it means the.

• die verlies = the loss

A useful thing to know is that die can also be used for plural the:

• die boek = the book
• die boeke = the books

So die does not tell you by itself whether something is singular or plural. You understand that from the noun and the rest of the sentence.

Because the sentence is talking about the loss, not a loss.

If you wanted to say A loss is serious, Afrikaans would use 'n:

• 'n verlies is ernstig = A loss is serious

So:

• die = the
• 'n = a / an

Yes. In this sentence, ernstig comes after is, so it stays ernstig.

But before a noun, it usually becomes ernstige:

• Die verlies is ernstig. = The loss is serious.
• die ernstige verlies = the serious loss

This is a very common pattern in Afrikaans:

• after is: basic adjective form
• before a noun: often -e form

A simple learner-friendly guide:

• Die ≈ dee
• verlies ≈ vur-LEES
• is ≈ iss
• ernstig ≈ AIRN-stekh or EHRN-stekh

A few notes:

• ie in die is usually like ee in see
• verlies has stress on the second syllable: ver-LEES
• the g in ernstig is the typical Afrikaans/Dutch-style throaty sound, not an English g

A rough full pronunciation: dee vur-LEES iss AIRN-stekh

Yes. verlies is related to the idea of loss, and it is also connected historically to verbs meaning to lose.

In Afrikaans:

• verlies = loss
• verloor = to lose

For example:

• Ons ly verlies. = We suffer loss.
• Ek verloor my sleutels. = I lose my keys.

So it helps to connect:

• verloor → action: lose
• verlies → noun: loss

Yes. Ernstig often means serious, but depending on context it can also suggest things like:

• grave
• severe
• earnest in some contexts

In Die verlies is ernstig, the most natural meaning is:

• The loss is serious or
• The loss is severe / grave

So the exact English wording can shift a little depending on context, but serious is the safest basic meaning here.

In the present tense, is is used very widely with all persons:

• Ek is = I am
• Jy is = you are
• Hy/Sy is = he/she is
• Ons is = we are
• Julle is = you are (plural)
• Hulle is = they are

So unlike English, Afrikaans does not change between am / is / are in the present tense. It just uses is.

Yes. The plural of verlies is verliese.

Examples:

• die verlies = the loss
• die verliese = the losses

So if you wanted a plural sentence, you could say:

• Die verliese is ernstig. = The losses are serious.

Notice that is stays is, even with a plural subject.

Yes, it is natural and grammatical.

It sounds like a formal or neutral statement, especially in contexts such as:

• finance
• business
• war or disaster reporting
• medical or emotional discussion
• legal or official writing

Depending on context, a speaker might also choose a more specific adjective, but Die verlies is ernstig is perfectly normal Afrikaans.