Το σφουγγάρι αγγειοπλαστικής και το εργαλείο χάραξης είναι βρεγμένα.

It has a very common Greek pattern:

• Το σφουγγάρι αγγειοπλαστικής = the pottery sponge
• και = and
• το εργαλείο χάραξης = the carving tool / scoring tool
• είναι = are
• βρεγμένα = wet

So the structure is:

[noun phrase] + και + [noun phrase] + είναι + [predicate adjective]

The two things joined by και form the subject of the sentence.

Because both nouns are definite: the sponge and the tool.

In Greek, when two definite nouns are joined with και, it is very normal to repeat the article:

• το σφουγγάρι ... και το εργαλείο ...

This is the most natural way to say the sponge and the tool.

If you left out the second το, the sentence would usually sound incomplete or less natural here.

You can tell because they take the article το, which is the neuter singular definite article.

So:

• το σφουγγάρι = neuter singular
• το εργαλείο = neuter singular

This is something you mostly learn together with the noun. Greek nouns have grammatical gender, and it does not always match natural gender or English expectations.

They are functioning as the subject of the sentence, so they are in the nominative.

A useful detail: for many neuter nouns, the nominative and accusative singular look the same. So the form itself does not change here, but its job in the sentence is nominative because these are the things that are wet.

They are both genitive singular forms.

• αγγειοπλαστικής = of pottery / for pottery
• χάραξης = of carving / for carving / for incising

Greek often uses the genitive where English might use:

• another noun before the main noun, as in pottery sponge
• of
• for

So:

• σφουγγάρι αγγειοπλαστικής literally = sponge of pottery
• εργαλείο χάραξης literally = tool of carving

But in natural English, you usually translate them more smoothly as:

• pottery sponge
• carving tool or scoring tool

Because the two singular nouns together make a compound subject:

• the sponge and the tool

That is plural in meaning, so Greek uses a plural predicate adjective.

Since both nouns are neuter, the adjective becomes neuter plural:

• singular neuter: βρεγμένο = wet
• plural neuter: βρεγμένα = wet

So Greek is agreeing with the whole subject, not with just the nearest noun.

Because predicate adjectives in Greek agree with the noun or nouns they describe in gender and number.

Here, the subject is made up of two neuter singular nouns joined by και, so together they take:

• plural agreement
• neuter gender

That gives you βρεγμένα.

If the sentence had only one of the objects, you would use the singular:

• Το σφουγγάρι είναι βρεγμένο.
• Το εργαλείο είναι βρεγμένο.

Because in the present tense of είμαι = to be, the form είναι is used for both:

• he/she/it is
• they are

So:

• Το εργαλείο είναι βρεγμένο. = The tool is wet.
• Τα εργαλεία είναι βρεγμένα. = The tools are wet.

Greek relies on context to tell you whether είναι means is or are.

In this sentence, it functions as an adjective meaning wet.

Its dictionary form is usually given as:

• βρεγμένος, βρεγμένη, βρεγμένο

Even though forms like this are historically related to participles, for a learner it is best to think of βρεγμένος as a normal adjective that changes for gender and number.

Here you need the neuter plural form:

• βρεγμένα

No. In this sentence, the adjective refers to both objects together, not just the nearest noun.

So Greek uses plural agreement:

• Το σφουγγάρι ... και το εργαλείο ... είναι βρεγμένα.

If you used βρεγμένο, it would sound like you were describing only one neuter singular thing, not both.

No, Greek word order is fairly flexible, but the given order is the most neutral and straightforward.

Neutral order:

• Το σφουγγάρι αγγειοπλαστικής και το εργαλείο χάραξης είναι βρεγμένα.

You could move things around for emphasis, for example:

• Βρεγμένα είναι το σφουγγάρι αγγειοπλαστικής και το εργαλείο χάραξης.

But that sounds more marked or emphatic. For learners, the original order is the safest one to use.

Yes, grammatically you could, if the context already makes it clear which sponge and which tool you mean.

For example:

• Το σφουγγάρι και το εργαλείο είναι βρεγμένα.

That means The sponge and the tool are wet.

The genitive words αγγειοπλαστικής and χάραξης simply make the nouns more specific.

The written accents show you the stressed syllable:

• Το σφουγγάρι
• αγγειοπλαστικής
• και
• το εργαλείο
• χάραξης
• είναι
• βρεγμένα

A rough pronunciation guide:

• σφουγγάρι ≈ sfou-GA-ri
• αγγειοπλαστικής ≈ an-yi-o-plas-TI-kis
• εργαλείο ≈ er-ga-LI-o
• χάραξης ≈ HA-ra-xis
• είναι ≈ EE-ne
• βρεγμένα ≈ vre-GME-na

You do not need perfect English-style phonetics here; the most important thing is to put the stress on the accented syllable.

It is basically neutral standard Greek.

Nothing in it is especially slangy or especially formal. It sounds like a normal descriptive sentence you might see in instructions, a classroom, a workshop, or a product description.

The only slightly specialized part is the vocabulary:

• αγγειοπλαστικής = related to pottery/ceramics
• χάραξης = related to carving/incising/scoring

So the grammar is everyday Greek, even if the nouns are somewhat technical.