Im Kurs lesen wir abwechselnd laut vor, wobei ich wichtige Wörter mit dem Textmarker markiere.

Im is a contraction of in dem.

• der Kurs is a masculine noun
• after in in this sentence, German uses the dative
• so in dem Kurs becomes im Kurs

Here, im Kurs means in class / during the course.

So:

• der Kurs = the course/class
• in dem Kurs = in the course
• im Kurs = shortened, normal version

Because the verb is vorlesen, which is a separable verb.

• infinitive: vorlesen = to read aloud
• in a normal main clause, the prefix separates:
  • Wir lesen ... vor.

So the sentence structure is:

• lesen = the main verb part, in second position
• vor = the separable prefix, moved to the end of the clause

Example:

• Ich lese den Text vor.
• Wir lesen abwechselnd laut vor.

Abwechselnd means something like:

• taking turns
• alternately
• one after another

In this sentence, it means that the people in the class are reading aloud in turns, not all at once.

So Wir lesen abwechselnd laut vor means the class members read aloud one after another.

Yes, vorlesen already includes the idea of reading something out loud to others.

But laut is still often added for emphasis or clarity. It can make the action sound more explicitly audible.

So:

• vorlesen = to read aloud / read out
• laut vorlesen = to read aloud, with extra emphasis on the fact that it is spoken out loud

This is natural German, even if it feels slightly repetitive from a learner’s point of view.

German word order is more structured than English here.

In a main clause:

1. the finite verb goes in second position
2. the subject often comes right after it
3. the separable prefix goes to the end

So:

• Im Kurs = first element
• lesen = finite verb in second position
• wir = subject
• abwechselnd laut = adverbs
• vor = separable prefix at the end

That gives:

Im Kurs lesen wir abwechselnd laut vor.

German does allow some flexibility with adverb placement, but not complete freedom. Vor must stay at the end of the clause because it belongs to vorlesen.

In this sentence, wobei means something like:

• while
• with
• in the process of which

It introduces an additional action happening at the same time as the main one.

So:

• Im Kurs lesen wir abwechselnd laut vor
• wobei ich wichtige Wörter mit dem Textmarker markiere

means roughly:

In class we take turns reading aloud, while I mark important words with a highlighter.

A very literal translation of wobei often sounds awkward in English, so while is usually the best natural translation here.

Because wobei introduces a subordinate clause, and in German subordinate clauses the conjugated verb normally goes to the end.

So:

• wobei ich wichtige Wörter mit dem Textmarker markiere

Structure:

• wobei = subordinating word
• ich = subject
• wichtige Wörter = object
• mit dem Textmarker = prepositional phrase
• markiere = verb at the end

This is a very common German pattern.

Because wichtige Wörter is accusative plural without an article, and that uses strong adjective endings.

The noun is:

• das Wort = word
• plural: die Wörter

Here it is the direct object of markiere, so it is in the accusative plural.

Since there is no article before it, the adjective must carry the grammatical ending itself:

• wichtige Wörter

Compare:

• ich markiere wichtige Wörter = I mark important words
• ich markiere die wichtigen Wörter = I mark the important words

With die, the adjective changes to wichtigen.

Because mit always takes the dative case.

The noun is:

• der Textmarker = the highlighter

After mit, masculine singular becomes:

• dem Textmarker

So:

• mit dem Textmarker = with the highlighter

This phrase expresses the instrument/tool used to do the action.

Der Textmarker means highlighter.

It is the pen used to mark text with bright color.

So:

• mit dem Textmarker markieren = to highlight / mark with a highlighter

In English, you might simply say I highlight important words, but German often uses:

• wichtige Wörter mit dem Textmarker markieren

Because wobei introduces a subordinate clause, and subordinate clauses in German are normally separated by a comma.

So the comma shows the boundary between:

• the main clause: Im Kurs lesen wir abwechselnd laut vor
• the subordinate clause: wobei ich wichtige Wörter mit dem Textmarker markiere

This comma is required in standard German.

Because the sentence describes two related actions, but not necessarily with the same subject.

• wir = we read aloud in turns
• ich = I mark important words

So the first action involves the group, while the second action is specifically done by the speaker.

That is completely normal in German. The subordinate clause introduced by wobei can have a different subject from the main clause.

Sometimes yes, but the meaning would shift slightly.

• während mainly means while/during
• wobei often links a second action more loosely, like while / in the process, with that happening

So:

• ..., während ich wichtige Wörter markiere = more straightforward while I mark important words
• ..., wobei ich wichtige Wörter markiere = sounds a bit more like an accompanying action or detail

In this sentence, wobei sounds natural because the second clause adds extra information about what is happening during the class activity.