Η κατανόηση κειμένου και η προφορική συμμετοχή είναι δυνατά σημεία.

Literally, it means comprehension of text or text comprehension.

In more natural English, this is often expressed as reading comprehension. Greek often uses a noun + genitive structure where English might prefer an adjective or a compound noun.

• κατανόηση = understanding, comprehension
• κειμένου = of a text / of text

So η κατανόηση κειμένου is a standard way to talk about the skill of understanding written text.

Because it is in the genitive case.

The base form is:

• το κείμενο = the text

But after a noun like κατανόηση (understanding / comprehension), Greek often uses the genitive to show of:

• κατανόηση κειμένου = comprehension of a text / of text

So:

• κείμενο = nominative / accusative singular
• κειμένου = genitive singular

This is very common in Greek with abstract nouns:

• διδασκαλία αγγλικών = teaching of English / English teaching
• ανάγνωση βιβλίου = reading of a book

Yes. Η κατανόηση του κειμένου is also correct.

The difference is mainly one of specificity:

• κατανόηση κειμένου = text comprehension in general, as a skill or category
• κατανόηση του κειμένου = comprehension of the text, a specific text

So in something like a school report or list of abilities, κατανόηση κειμένου sounds very natural because it refers to a general skill.

Because Greek is saying the reading comprehension and the oral participation, meaning two separate noun phrases joined by και.

• η κατανόηση κειμένου
• η προφορική συμμετοχή

Repeating the article is normal and often preferred when two distinct items are listed. It makes the structure clearer.

English often leaves articles out in this kind of general statement, but Greek uses them more regularly with abstract nouns.

Because it is an adjective agreeing with συμμετοχή.

• συμμετοχή is feminine singular
• so the adjective must also be feminine singular

That gives:

• η προφορική συμμετοχή = oral participation

Here are the matching forms of the adjective:

• προφορικός = masculine
• προφορική = feminine
• προφορικό = neuter

Greek adjectives must agree with the noun in gender, number, and case.

It means oral participation or spoken participation, especially in a classroom context.

• προφορική = oral, spoken
• συμμετοχή = participation

So this refers to taking part by speaking, answering questions, contributing aloud, and so on.

In school language, this is a very common phrase.

Because δυνατά describes σημεία, not κατανόηση or συμμετοχή.

The structure is:

• Η κατανόηση κειμένου και η προφορική συμμετοχή = the subject
• είναι δυνατά σημεία = are strong points

So the predicate noun phrase is δυνατά σημεία:

• σημεία = points
• δυνατά = strong

Since σημεία is neuter plural, the adjective is also neuter plural:

• δυνατό = strong (neuter singular)
• δυνατά = strong (neuter plural)

This is like English They are strong points, where strong belongs to points, not directly to the earlier nouns.

Yes, literally it means points, but in this context δυνατά σημεία is an idiomatic expression meaning:

• strong points
• strengths

So the whole sentence means that reading comprehension and oral participation are strengths.

Greek often uses δυνατό σημείο / δυνατά σημεία in exactly this figurative sense.

It works for both singular and plural in the present tense.

That is why:

• Αυτό είναι καλό. = This is good.
• Αυτά είναι καλά. = These are good.

In your sentence, the subject is plural in meaning because it contains two things joined by και, and είναι is still the correct form.

So you do not need a different word for are. Greek uses είναι for both is and are.

The main subject nouns are in the nominative:

• η κατανόηση
• η συμμετοχή

That is because they are the subject of the sentence.

Inside the first phrase, κειμένου is in the genitive because it depends on κατανόηση.

Then σημεία is also in the nominative plural because it is the predicate noun after είναι.

So, simplified:

• η κατανόηση = nominative
• κειμένου = genitive
• η προφορική συμμετοχή = nominative
• δυνατά σημεία = nominative plural predicate

Yes, Greek word order is more flexible than English, though the original version is the most neutral and natural.

For example, you could also say:

• Δυνατά σημεία είναι η κατανόηση κειμένου και η προφορική συμμετοχή.

This gives a little more emphasis to strong points.

Still, the original sentence is probably the best choice in a report-style or descriptive context:

• Η κατανόηση κειμένου και η προφορική συμμετοχή είναι δυνατά σημεία.

Because Greek does not always need the article in predicate expressions after είναι.

So:

• είναι δυνατά σημεία = are strong points

This is natural Greek. Adding the article would change the feel and could make it sound more specific or less natural in this kind of evaluation.

Greek often leaves the article out in this position when describing what something is.

It sounds very natural and fairly formal, like something a teacher might write in an assessment.

It has the tone of:

• Reading comprehension and oral participation are strengths.

This kind of phrasing is common in comments about a student's performance, because it names specific skill areas in a concise, professional way.