ترأس المتحدث حلقة النقاش للتو.

Because Arabic often uses verb–subject–object order, especially in formal written MSA.

So:

• ترأس = the verb
• المتحدث = the subject
• حلقة النقاش = the object

This word order is very normal and natural in news-style or formal Arabic.
You could also say المتحدث ترأس حلقة النقاش للتو. That is also correct, but it puts a bit more focus on the speaker.

ترأس means headed, chaired, or presided over.

So in this sentence, it does not mean simply spoke. It means the speaker was leading or chairing the discussion.

A good way to think of it is:

• تحدث = spoke
• ترأس = chaired / headed

In Arabic, the verb already shows person, gender, and number, so a separate pronoun like هو is usually unnecessary.

Here, ترأس is a past tense, 3rd person masculine singular verb, so it already tells you he chaired.

Then المتحدث comes after it as the explicit subject:

• ترأس = he chaired
• المتحدث = the speaker

So Arabic does not need to say the equivalent of he the speaker chaired.

Grammatically, yes. المتحدث is masculine singular.

The feminine form would be المتحدثة.

Depending on context, المتحدث can mean:

• speaker
• spokesperson
• presenter
• person speaking

In this sentence, speaker is the most natural meaning.

Because حلقة النقاش is an iḍāfa construction, often called a genitive/possessive construction.

It literally means something like:

• حلقة = circle / session / panel
• النقاش = the discussion

Together: discussion panel or panel discussion

In an iḍāfa:

• the first noun usually does not take ال
• the second noun can make the whole phrase definite

So even though حلقة has no ال, the whole phrase حلقة النقاش can still mean the panel discussion because النقاش is definite.

Yes, حلقة النقاش is a common expression.

Literally, حلقة can mean ring, circle, or episode, but in contexts like meetings and events it can refer to a session, forum, or panel.

So حلقة النقاش is best understood as a unit meaning:

• discussion panel
• panel discussion
• discussion session

It is better not to translate it too literally as discussion circle unless the context really is a circle.

That is just a difference between Arabic and English.

In Arabic, ترأس commonly takes a direct object with no preposition:

• ترأس الاجتماع = he chaired the meeting
• ترأس الجلسة = he presided over the session

So in your sentence, حلقة النقاش is the direct object of ترأس.

English uses preside over, but Arabic simply uses ترأس + object.

للتو means just now, a moment ago, or simply just.

It tells you that the action happened very recently.

So:

• ترأس المتحدث حلقة النقاش للتو = The speaker just chaired the panel discussion.

This expression is often placed near the end of the sentence, as it is here.

Also, it is best learned as a fixed expression. You do not need to analyze it literally in order to use it correctly.

It is pronounced roughly taraʾʾasa.

The important thing for learners is the hamza sound in the middle. Do not smooth it out too much.

So not:

• tarasa

But more like:

• tara-ʾʾa-sa

Also, in the sentence:

• النقاش is pronounced an-niqāsh in connected speech, because ن is a sun letter
• للتو is pronounced with an assimilated t sound as well

You do not need perfect phonetic detail at first; the main tricky part is noticing the hamza in ترأس.

They are:

• المتحدث = the subject
• حلقة = the direct object
• النقاش = the second noun in an iḍāfa construction

If full case endings were written, you would expect:

• the subject to be nominative
• the direct object to be accusative
• the second part of the iḍāfa to be genitive

So this sentence is a nice example of how Arabic marks relationships very clearly, even though everyday writing often leaves off the short vowels.

Yes, absolutely.

That version is also correct, but it uses subject–verb–object order instead of verb–subject–object.

The difference is mostly about style and emphasis:

• ترأس المتحدث حلقة النقاش للتو = more neutral/formal, very natural in written MSA
• المتحدث ترأس حلقة النقاش للتو = puts a little more focus on the speaker

Both are grammatical.