Learn Hardcore German: Jede Lernerfahrung macht mich im Unterricht sicher. - Each learning experience makes me confident in class.

Erfahrung is a feminine noun: die Erfahrung, so the compound die Lernerfahrung is also feminine.
The word jede behaves like diese / welche etc. and agrees with the noun:
- jeder – masculine (e.g. jeder Tag)
- jede – feminine (e.g. jede Lernerfahrung)
- jedes – neuter (e.g. jedes Wort)

Here, we need the feminine nominative singular form: jede.

What is the grammatical role of Jede Lernerfahrung in this sentence?

Jede Lernerfahrung is the subject of the sentence.

Breakdown:

Subject (nominative): Jede Lernerfahrung – what is doing the action / causing the effect.
Verb: macht.
Direct object (accusative): mich – the person being affected.
Predicate adjective relating to the object: sicher.
Adverbial phrase of place/context: im Unterricht.

So the structure is roughly:
[Subject] makes [object] [adjective] [where/when].

Why is it mich and not mir?

Because mich is accusative (direct object), and the verb machen here takes a direct object + predicate adjective:

etwas macht jemanden sicher
(something makes someone confident)

Patterns:

jemandEN (accusative) + sicher
jemandEM (dative) would be used with other verbs/structures, e.g.
Mir ist sicher – which doesn’t work here.

More examples of the same pattern:

Das macht mich glücklich. – That makes me happy.
Die Übung macht ihn müde. – The exercise makes him tired.

So: macht mich sicher, not macht mir sicher.

What exactly is sicher expressing here?

In this context, sicher means confident / self-assured, not safe.

German sicher can mean:

safe, secure:
Wir sind hier sicher. – We’re safe here.
certain, sure:
Ich bin mir sicher. – I am sure.
confident (about one’s ability in a context):
Ich fühle mich im Unterricht sicher. – I feel confident in class.

In the sentence, sicher refers to feeling more confident when participating in class or during lessons.

Why is it im Unterricht and not in dem Unterricht?

im is simply the contracted form of in dem:

in (preposition) + dem (dative article, masculine/neuter) → im

Since Unterricht is masculine (der Unterricht) and in here requires the dative (location: where?), we would have:

in dem Unterricht → commonly contracted to im Unterricht.

The contraction is normal and much more natural in speech and writing.

What does im Unterricht mean here: “in class” or “during lessons”?

Im Unterricht can mean both “in class” and “during lessons”; it describes the context of formal learning situations.

It usually refers to:

being in a classroom situation,
participating in a lesson or course,
the time and situation when teaching is taking place.

So mich im Unterricht sicher = feel confident when I am in class / participating in lessons.

Why is im Unterricht at the end of the sentence and not earlier?

German word order is more flexible than English, and adverbials (like im Unterricht) often go toward the end.

The neutral pattern is:

Subject – Verb – Object – Other information (time, place, manner, etc.)

So:

Jede Lernerfahrung (subject)
macht (verb)
mich (object)
im Unterricht sicher (where/when am I confident)

You could move im Unterricht:

Im Unterricht macht jede Lernerfahrung mich sicher.
(Focus on “in class”.)
Jede Lernerfahrung im Unterricht macht mich sicher.
(Now “every learning experience in class” is the subject.)

All are grammatical, but the meaning and emphasis shift:

Original: each learning experience (wherever it happens) makes me confident in class.
Jede Lernerfahrung im Unterricht…: every learning experience that happens in class makes me confident (generally).

What is the function of sicher grammatically? Is it just an adjective?

Yes, it’s an adjective, but specifically used as a predicate adjective related to the object.

The pattern is:

etwas macht jemanden + Adjektiv
- Subject: etwas (here: jede Lernerfahrung) – nominative
- Object: jemanden (here: mich) – accusative
- Predicate adjective: sicher – describes the state of the object.

Similar patterns:

Die Nachricht macht mich froh. – The news makes me happy.
Das Training macht ihn stark. – The training makes him strong.

Could we say Jede Lernerfahrung macht mich im Unterricht sicherer instead? What’s the difference?

Yes, sicherer (comparative) is possible, and the meaning changes slightly:

sicher = confident
sicherer = more confident

Nuance:

macht mich sicher – gives me (a sense of) confidence in class; suggests reaching a stable level of confidence.
macht mich sicherer – makes me more confident than before; focuses on the increase, step by step.

Both are correct; which you choose depends on what you want to express.

Why is Lernerfahrung one long word and not Lern Erfahrung?

German very often builds compound nouns by combining two (or more) nouns into one:

Lern- (from lernen, learning) + Erfahrung (experience)
→ Lernerfahrung (learning experience)

Writing Lern Erfahrung as two separate words would be incorrect. In German, compounds like:

Sprachkurs (language course)
Hausaufgabe (homework)
Lernerfahrung (learning experience)

are normally written as a single word.

Could we also say Alle Lernerfahrungen machen mich im Unterricht sicher? What would change?

Yes, that’s grammatically correct, but the meaning shifts slightly:

Jede Lernerfahrung macht mich im Unterricht sicher.
Focuses on each individual experience: every single learning experience contributes to your confidence.
Alle Lernerfahrungen machen mich im Unterricht sicher.
Focuses on all experiences taken together as a group: the total of all learning experiences makes you confident.

Both are fine; jede emphasizes the effect of each single experience, one by one.