Learn Hardcore German: Nach dem Spiel kommentiert die Trainerin ruhig unsere Fehler. - After the game the coach female calmly comments on our mistakes.

German has a verb‑second rule in main clauses: the conjugated verb must be in the second position, but the first position can be almost anything (subject, time phrase, object, etc.).

By putting Nach dem Spiel first, you emphasize when something happens:

Nach dem Spiel kommentiert die Trainerin ruhig unsere Fehler.
Focus: After the game, the coach comments on our mistakes.

You could also say:

Die Trainerin kommentiert nach dem Spiel ruhig unsere Fehler.

Both are correct. The difference is mainly in emphasis and style. Starting with the time phrase is very common in German.

Why is it nach dem Spiel and not nach das Spiel or nach den Spiel?

The preposition nach always takes the dative case when it means “after” (in time).

das Spiel = nominative/accusative, neuter
dem Spiel = dative, neuter

Since nach requires dative, and Spiel is neuter, you must use:

nach + dem (dative neuter) → nach dem Spiel

Nach das Spiel or nach den Spiel is ungrammatical in this meaning.

Why do we need the article at all? Why not just Nach Spiel?

In German, you normally use an article with concrete countable nouns like Spiel.

Nach dem Spiel = after the (specific) game

Leaving the article out (Nach Spiel) would sound wrong here. There are set expressions without articles (e.g. nach Hause, zu Fuß), but Spiel is not used that way in this context.

Why is the verb kommentiert in that form?

The infinitive is kommentieren.
In the present tense:

ich kommentiere
du kommentierst
er/sie/es kommentiert
wir kommentieren
ihr kommentiert
sie/Sie kommentieren

The subject is die Trainerin = she → 3rd person singular.
So you must use the form kommentiert.

That’s why the sentence has:

Die Trainerin kommentiert …

In English we might say “will comment.” Why is German using present tense kommentiert for a future action?

German often uses the present tense to talk about the near future, especially when there is a time expression:

Nach dem Spiel kommentiert die Trainerin unsere Fehler.
= After the game, the coach will comment on our mistakes.

The future tense (wird kommentieren) is possible but less common in everyday speech here:

Nach dem Spiel wird die Trainerin unsere Fehler kommentieren.

Both are correct; the simple present is more natural.

Why is it die Trainerin and not der Trainer?

German often marks grammatical gender with word endings.

der Trainer = male coach (or grammatically masculine, if gender is unspecified)
die Trainerin = female coach (specifically feminine)

The ending -in is the common feminine ending for many professions and roles:

der Lehrer → die Lehrerin (teacher)
der Arzt → die Ärztin (doctor)

So die Trainerin tells you that the coach is female.

Why is die Trainerin the subject?

The subject is the person or thing performing the action of the verb.

Who is doing the commenting? → die Trainerin

So die Trainerin is in the nominative case (subject case):

die Trainerin kommentiert …

You can also see this from word order: in a main clause, it’s normally:

[something in first position] + verb (2nd)
- subject
  - rest

Here:

Nach dem Spiel (1st position)
kommentiert (verb, 2nd position)
die Trainerin (subject, follows the verb)

Why is it unsere Fehler and not unsere Fehlern?

Two things are going on:

Case:
- unsere Fehler is the direct object of kommentiert, so it’s in the accusative case.
- For plural nouns, the accusative form of Fehler is the same as the nominative:
  - nominative plural: die Fehler
  - accusative plural: die Fehler There is no -n added here.
Possessive determiner:
- The base form is unser (our).
- In the accusative plural, the form is unsere:
  - unsere Fehler (our mistakes)

So unsere Fehler is correct; unsere Fehlern would be wrong here.

Why does Fehler look the same in singular and plural?

Some German nouns have the same form in singular and plural; the plural is marked only by the article or context.

singular: der Fehler = the mistake
plural: die Fehler = the mistakes

You recognize the plural here from:

the article (in other sentences), and
the context: unsere Fehler → our mistakes (plural meaning).

Why is it unsere Fehler and not unseren Fehler or unserer Fehler?

Unser- behaves like an adjective and must agree with:

person: wir → unser-
number: plural (Fehler)
case: accusative plural (direct object)

Declension of unser- (strong) in accusative:

masculine singular: unseren Mann
neuter singular: unser Kind
feminine singular: unsere Frau
plural (all genders): unsere Kinder / Fehler / Bücher

Because Fehler is plural accusative, you need unsere:

unsere Fehler

What exactly is ruhig here – an adjective or an adverb? And what does it mean?

In this sentence, ruhig functions as an adverb modifying the verb kommentiert: it describes how she comments.

Possible meanings depending on context:

calmly (without agitation, in a composed way)
sometimes quietly (in a low voice), though leise is more typical for “quiet(ly)”

As an adjective, ruhig can mean:

ein ruhiger Mensch = a calm person
ein ruhiger Ort = a quiet place

Here it is adverbial: Sie kommentiert ruhig → She comments calmly.

Could ruhig be placed somewhere else in the sentence, and would that change the meaning?

Yes, you have some flexibility with adverbs like ruhig. All of these are grammatical:

Nach dem Spiel kommentiert die Trainerin ruhig unsere Fehler.
Nach dem Spiel kommentiert die Trainerin unsere Fehler ruhig.
Die Trainerin kommentiert nach dem Spiel ruhig unsere Fehler.

The basic meaning (she comments calmly) stays the same, though native speakers have preferences for what sounds most natural.
Placing ruhig right after the verb (kommentiert ruhig) is very typical and sounds natural.

Why is there no preposition like “on” after kommentiert, even though in English we say “comment on our mistakes”?

In German, kommentieren is a transitive verb and usually takes a direct object in the accusative case:

etwas kommentieren = to comment on something

Examples:

den Artikel kommentieren = to comment on the article
das Spiel kommentieren = to comment on the game
unsere Fehler kommentieren = to comment on our mistakes

So you do not say auf unsere Fehler kommentieren in standard German; that would be incorrect in this meaning.

Why are Spiel, Trainerin, and Fehler capitalized?

In German, all nouns are capitalized, regardless of where they appear in the sentence.

das Spiel → Spiel
die Trainerin → Trainerin
der Fehler → Fehler

This rule is one of the most visible differences from English spelling.