Die plastiek is droog.

Die is the definite article, so it means the.

In Afrikaans, die is used much more broadly than English the in the sense that it does not change for gender. It is the normal definite article for nouns like plastiek.

So Die plastiek = the plastic.

In Afrikaans, die is usually pronounced like dee.

So it is not pronounced like the English verb die.

This is the normal word order for a simple statement in Afrikaans:

subject + verb + adjective/complement

So here you have:

• Die plastiek = subject
• is = verb
• droog = adjective

This is very similar to English The plastic is dry.

Mostly yes. Is is the present-tense form of to be in this sentence.

A useful thing for learners is that Afrikaans does not conjugate this verb as much as English does in the present tense. You get:

• ek is
• jy is
• hy/sy is
• ons is
• julle is
• hulle is

So is stays the same with different subjects.

Because it is being used after the verb is as a predicate adjective.

In Afrikaans, adjectives used this way usually stay in their basic form:

• Die plastiek is droog
• Die tafel is groot
• Die water is koud

So droog does not need an ending here.

Yes, often it would.

When an adjective comes before a noun, Afrikaans often uses an attributive form. For droog, that form is droë:

• die droë plastiek = the dry plastic

So compare:

• Die plastiek is droog
• die droë plastiek

This is a very common pattern in Afrikaans.

Usually plastiek means plastic as a material.

In Die plastiek is droog, it most naturally refers to a specific piece, amount, or type of plastic that both speaker and listener know about.

If you wanted to talk about plastic in general, Afrikaans can also say:

• Plastiek is droog

That would sound more general, while Die plastiek sounds more specific.

Sometimes, yes, but it changes the meaning slightly.

• Die plastiek is droog = the plastic is dry, a specific plastic item/material
• Plastiek is droog = plastic is dry, or plastic is dry in this context more generally

So whether you include die depends on whether you mean the specific plastic or plastic in general.

Afrikaans normally uses a double nie structure for negation:

Die plastiek is nie droog nie.

That means The plastic is not dry.

A simple way to see it is:

• first nie comes after the verb or predicate area
• second nie comes at the end of the clause

A rough guide is:

• plastiek ≈ plahs-TEEK
• droog ≈ drohkh

A few helpful notes:

• ie in Afrikaans is usually a long ee sound
• oo in droog is a long vowel
• the final g is not like English g in go; it is a throat sound, similar to the ch sound in some Scottish or Dutch pronunciations

So the whole sentence is roughly:

dee plahs-TEEK is drohkh

Yes. It is a completely normal, grammatical Afrikaans sentence.

It is short and simple, but native speakers would understand it easily. It follows standard Afrikaans grammar and sounds natural in the right context.