Learn Hardcore French: Le professeur explique la nuance entre deux expressions que nous confondons. - The teacher explains the nuance between two expressions that we confuse.

Le professeur = the teacher/professor (a specific one that is known in the context – for example, the one teaching this class).
Un professeur = a teacher/professor (not a specific one; any teacher).
Bare professeur (without an article) is generally not correct in normal sentences.

In this sentence, we are talking about a specific teacher who is explaining something, so the definite article le is used, just like English often would say the teacher in a classroom context:

Le professeur explique…
The teacher is explaining…

You might see bare Professeur used as a form of address, like a title:

Bonjour, Professeur !
Hello, Professor!

But in a normal sentence with a subject, you need le professeur (or un professeur, depending on meaning).

Why is it le professeur even if the teacher is a woman?

Traditionally, professeur is a grammatically masculine noun in French, regardless of the teacher’s biological sex. So grammatically you say:

Le professeur est très exigeant.
The teacher is very demanding.

Even if the teacher is a woman, the grammar traditionally stays masculine:

Le professeur est très exigeant. Elle donne beaucoup de devoirs.
The teacher is very demanding. She gives a lot of homework.

In modern usage, especially in some regions and contexts, people may write:

une professeure (feminine form, with an extra e)
or use the shortened familiar form une prof

But the sentence you have uses the traditional, standard form le professeur, which is grammatically masculine by default and does not automatically indicate the teacher’s gender.

How does explique work here? Isn’t there something missing like à quelqu’un?

The verb expliquer is usually structured as:

expliquer quelque chose à quelqu’un
to explain something to someone

In your sentence, only the “something” is expressed:

Le professeur explique la nuance…
The teacher explains the nuance…

The “to whom” part is simply not stated. In context, it’s obvious (probably “to us” / “to the class”), so French can leave it out:

Le professeur explique la nuance (à nous / à la classe).

If you want to include the person, you can say:

Le professeur nous explique la nuance…
The teacher explains the nuance to us…
Le professeur explique la nuance aux étudiants.
The teacher explains the nuance to the students.

So nothing is “wrong” or missing; the indirect object is just implicit.

Why is it la nuance and not la différence?

Both nuance and différence exist in French, but they don’t mean exactly the same thing:

la différence = the difference (often a clear, more obvious distinction)
la nuance = the nuance, a subtle difference in meaning, usage, tone, etc.

In this sentence, the teacher is explaining a subtle distinction between two expressions that are easy to confuse. Using la nuance highlights that the difference is not big and obvious, but fine and subtle.

You could say:

Le professeur explique la différence entre deux expressions…

That would still be correct, but it sounds less precise if you’re talking about a fine shade of meaning. La nuance fits better for explaining small, delicate distinctions.

How does entre work in entre deux expressions? Should there be an et?

Entre means between or among. When you specify the two items, you often see:

entre X et Y = between X and Y

For example:

la différence entre le français et l’anglais
the difference between French and English

In your sentence, the two expressions are not named. We only know there are two of them:

la nuance entre deux expressions
the nuance between two expressions

Because the two expressions are not listed individually, there is no et. If you wanted to name them, you would say:

Le professeur explique la nuance entre l’expression A et l’expression B.
The teacher explains the nuance between expression A and expression B.

What is que in que nous confondons doing? Is it a conjunction or something else?

In que nous confondons, the que is a relative pronoun, not a conjunction.

It refers back to deux expressions.
It acts as the direct object of the verb confondons.

You can think of it like this:

Le professeur explique la nuance entre deux expressions. Nous confondons ces expressions.
The teacher explains the nuance between two expressions. We confuse these expressions.

When you combine these two ideas with a relative clause, ces expressions becomes que:

Le professeur explique la nuance entre deux expressions que nous confondons.
Literally: The teacher explains the nuance between two expressions that we confuse.

Grammar points:

Antecedent of que: deux expressions
Function of que: direct object of confondons
Subject of confondons: nous

That’s why there is no preposition in front of que.

Could we use dont instead of que, like les expressions dont nous nous confondons?

No, dont is not correct here.

Dont is used mainly when the verb or expression in the relative clause normally takes de:

parler de quelque chose → les choses dont je parle
se souvenir de quelqu’un → la personne dont je me souviens

But confondre in the sense of “to mix up” or “to confuse (one thing with another)” does not take de:

confondre quelque chose avec autre chose
to confuse something with something else

In your sentence, we just have:

confondre ces expressions = to mix up these expressions

So we must use que (direct object), not dont.

Les expressions dont nous nous confondons would be ungrammatical; se confondre de is not a valid structure for this meaning.

Why is the verb confondons in the present tense and not in the subjunctive?

The clause que nous confondons expresses a simple fact:

We do confuse these expressions (habitually).

In French, the subjunctive is used mainly for uncertainty, doubt, desire, necessity, emotion, etc., often after certain expressions (like il faut que, je veux que, je doute que, bien que, etc.).

Here, there is no such trigger. The sentence states something that is presented as true:

…des expressions que nous confondons.
…expressions that we confuse.

So the indicative present (confondons) is exactly what we need.

If you artificially tried to force a subjunctive, it would sound wrong in standard French because the meaning is not about possibility or doubt, but about a known habit.

How does confondre work in this context? Why is there no avec?

Confondre has a few patterns, but in the sense of “to mix up / confuse one thing with another,” you’ll often see:

With a single direct object (general statement):
- Je confonds ces deux mots.
  I confuse these two words / I mix up these two words.
- Nous confondons ces expressions.
  We confuse these expressions.
In this pattern, adding avec is not necessary; the idea is “we mix them up (with each other).”
With an explicit second term, you can add avec:
- Je confonds le mot A avec le mot B.
  I confuse word A with word B.

In your sentence, we’re speaking generally about two expressions that we tend to mix up with each other, so French can simply say:

deux expressions que nous confondons
two expressions that we confuse (with one another)

The “with each other” idea is understood from context and the fact that there are two expressions.

Could we also say Le professeur nous explique la nuance entre deux expressions que nous confondons? What changes?

Yes, that is correct, and it’s a very natural alternative:

Le professeur nous explique la nuance entre deux expressions que nous confondons.
The teacher explains to us the nuance between two expressions that we confuse.

The only change is that you now explicitly mention who receives the explanation:

nous = to us (indirect object)

Structure:

Subject: Le professeur
Indirect object pronoun: nous
Verb: explique
Direct object: la nuance entre deux expressions que nous confondons

In the original sentence, nous is only present as the subject of the relative clause (que nous confondons). With nous explique, nous plays two roles:

nous (indirect object of explique) → recipient of the explanation
nous (subject of confondons) → people who confuse the expressions

This is grammatically fine and common in French.