Learn Hardcore German: Während der Vorlesung notiere ich mir zwischendurch Fragen in meinen kleinen Notizblock. - During the lecture I jot down questions in my little notepad from time to time.

colloquial: während dem Kurs (dative)
here, that would be während der Vorlesung too, but in this example it’s best interpreted as standard genitive, not colloquial dative.

Why does the verb come right after Während der Vorlesung instead of after ich?

German main clauses follow the verb-second rule: the finite verb must be the second element in the sentence.

Here, Während der Vorlesung is one block (a single adverbial phrase = “first element”), so the verb must come next:

Während der Vorlesung – first element
notiere – finite verb in second position
ich mir zwischendurch Fragen in meinen kleinen Notizblock – the rest

You could also start with the subject:

Ich notiere mir während der Vorlesung zwischendurch Fragen in meinen kleinen Notizblock.

Same meaning, just different emphasis.
The crucial point: in both versions, the finite verb (notiere) is in second position.

What is the function of mir in notiere ich mir? Why not just notiere ich?

mir is a dative pronoun showing that you are doing this action for yourself / for your own benefit.

Ich notiere Fragen.
= I write down questions. (neutral, just describing the action)
Ich notiere mir Fragen.
= I write down questions for myself, I jot them down for my own later use.

This “extra dative” is sometimes called a dative of interest or “ethic dative”. It’s similar to:

Ich koche mir einen Kaffee. – I make myself a coffee.
Ich kaufe mir ein neues Buch. – I buy myself a new book.

So notiere ich mir is very natural and idiomatic for “I jot questions down (for myself)”.

Can I leave out mir and just say Während der Vorlesung notiere ich Fragen …?

Yes, that is grammatically correct:

Während der Vorlesung notiere ich Fragen in meinen kleinen Notizblock.

However, you lose the nuance that this is for your own benefit.

With mir, it sounds more natural and personal in this context, like the typical thing a student does: jotting questions down to remember or ask later.

So:

Without mir: more neutral, a bit less idiomatic.
With mir: sounds like everyday, natural student language.

Why is it in meinen kleinen Notizblock and not in meinem kleinen Notizblock?

This is about the case after in and the meaning of the preposition:

in is a two-way preposition (Wechselpräposition) and can take:

dative: for location (where something is)
accusative: for direction (where something is going / movement into)

Here we have movement into the notebook: you are putting questions into it (metaphorically, by writing them there).

So we need accusative:

Masculine noun: der Notizblock
Accusative singular masculine article: den
With mein-: meinen Notizblock
With adjective: meinen kleinen Notizblock

If it were a static location, it would be dative:

Die Fragen stehen in meinem kleinen Notizblock.
(The questions are in my little notepad – no movement.)

But with notieren … in … we’re clearly expressing direction (writing into it), so accusative is correct: in meinen kleinen Notizblock.

How do the endings in meinen kleinen Notizblock work?

Breakdown:

Notizblock – masculine noun, singular
Case here: accusative (movement into something → in
- accusative)
Possessive determiner: mein-
Adjective: klein-

For masculine singular accusative after a possessive (like mein), the endings are:

Possessive: meinen
Adjective: kleinen
Noun: Notizblock

Pattern:

mein → meinen
klein → kleinen
Notizblock stays the same

So in meinen kleinen Notizblock is:

in
- accusative
masculine singular
possessive + adjective + noun, each with the correct ending for that pattern.

What exactly does zwischendurch mean here, and where can it go in the sentence?

zwischendurch is a time adverb that means roughly:

now and then
from time to time
in between

In this sentence it means you occasionally jot down questions during the lecture, not constantly.

Typical synonyms (with slightly different feel):

ab und zu
hin und wieder
gelegentlich

About placement: zwischendurch is quite flexible. All of these are possible:

Während der Vorlesung notiere ich mir zwischendurch Fragen in meinen kleinen Notizblock.
Während der Vorlesung notiere ich mir Fragen zwischendurch in meinen kleinen Notizblock.
Während der Vorlesung notiere ich mir Fragen in meinen kleinen Notizblock zwischendurch. (less common, sounds a bit tacked on)

The version given (after ich mir) is very natural and typical.
In general, time adverbs often go fairly early in the “middle field” (between the finite verb and the sentence-final elements).

What’s the difference between Notizblock, Notizbuch, and Heft?

All three can involve writing, but they’re used a bit differently:

Notizblock
= a pad or block of paper, usually with pages you can tear off.
Often smaller, may have a spiral or glue at the top or side. Used for quick notes, lists, phone messages.
Notizbuch
= a notebook or journal that’s bound like a book.
You usually don’t tear pages out. Used for more permanent notes, journaling, study notes, etc.
Heft
= an exercise book / school notebook (often a thin stapled booklet).
Very common in school contexts: Matheheft, Deutschheft, etc.

In this sentence, kleinen Notizblock suggests a small pad you carry with you to jot down things quickly during the lecture.

What exactly is a Vorlesung, and how is it different from Unterricht or Kurs?

Vorlesung
Literally “reading out”, but in modern usage: a lecture, especially at university.
Typically: a professor speaks, many students listen, not much interaction.
Unterricht
= lessons, teaching, instruction (often school context, but can be broader).
More interactive, smaller groups, like classes at school or language classes.
Kurs
= course, can be at university, in adult education, at a language school, etc.
It’s the whole course as an offering, not one specific lecture.

So Während der Vorlesung clearly places you in a university-style lecture context, not a school classroom lesson.

Can the word order be different, for example with zwischendurch or während der Vorlesung in other places?

Yes, German allows several natural variants with slightly different emphasis, as long as the finite verb stays in second position. Some common alternatives:

Start with the subject:
- Ich notiere mir während der Vorlesung zwischendurch Fragen in meinen kleinen Notizblock.
Emphasize zwischendurch:
- Zwischendurch notiere ich mir während der Vorlesung Fragen in meinen kleinen Notizblock.
Put während der Vorlesung later:
- Ich notiere mir zwischendurch während der Vorlesung Fragen in meinen kleinen Notizblock.

All are grammatical. The original version:

Während der Vorlesung notiere ich mir zwischendurch Fragen in meinen kleinen Notizblock.

puts the time frame “during the lecture” right up front, setting the scene first, which is very natural in German.