Learn Hardcore German: Dieser Hund trinkt Wasser.

Dieser is a demonstrative determiner meaning “this”. In German, demonstratives agree in gender, number, and case with the noun they modify. Here, Hund is masculine, singular, and in the nominative case (because it’s the subject of the sentence). The correct masculine nominative form is Dieser.

Diese would be feminine nominative (e.g. diese Katze).
Dieses would be neuter nominative (e.g. dieses Kind).

Why is Hund in the nominative case here?

In German, the nominative case marks the subject of a sentence—the person or thing performing the action. Since Hund is performing the action trinkt (“drinks”), it must be in the nominative case. You can spot the nominative by asking “Who or what is drinking?” → “Dieser Hund.”

Why is the verb trinkt at the second position in the sentence?

German main clauses follow the verb-second (V2) word order. That means the finite verb must come in the second position, regardless of what comes first (subject, adverb, etc.). Here the subject “Dieser Hund” is first, so the verb “trinkt” comes second.

Why does trinken become trinkt? How do we form that?

Trinken is the infinitive. To conjugate it for the third person singular in present tense (he/she/it), you:

Remove -en → stem trink-
Add -t → trinkt
So er trinkt, sie trinkt, es trinkt.

What case is Wasser, and how do we know?

Wasser is in the accusative case, because it’s the direct object of the verb (the thing being drunk). You identify the accusative by asking “What does the dog drink?” → “(Er trinkt) Wasser.”

Why is there no article before Wasser?

Wasser is an uncountable, mass noun here (like English “water”). In German, mass nouns often appear without an article when speaking generally or about an indefinite quantity.

If you wanted specific water, you could say “Dieser Hund trinkt das Wasser.”
If you wanted some water explicitly, you could use “ein wenig Wasser” or “etwas Wasser.”

Can we replace Dieser Hund with Der Hund? What’s the difference?

Yes, you can say “Der Hund trinkt Wasser.”

Dieser Hund = “This dog” (points to a specific dog).
Der Hund = “The dog” (refers to a known dog in general).
Both use the nominative masculine article/determiner, but the nuance of specificity changes.

How would you say “A dog drinks water” in German?

You’d use the indefinite article ein for masculine nominative:
“Ein Hund trinkt Wasser.”
This means “A dog drinks water,” making it a generic statement about any dog.

How do you express “This dog is drinking water right now”?

German doesn’t have a progressive form like English “is drinking.” Instead, you add a time adverb such as “gerade” (just/at this moment):
“Dieser Hund trinkt gerade Wasser.”
Literally: “This dog drinks water just now.”