Learn Hardcore Finnish: Tarvitsen vettä nyt.

In Finnish, vettä is the partitive form of vesi (“water”). The partitive case often indicates an uncountable or indefinite amount. Because water in this context is not a specific, countable thing and you just need some quantity of it, vettä is used rather than vesi, which is the nominative (basic form).

Why is it correct to say Tarvitsen vettä nyt without explicitly saying Minä tarvitsen vettä nyt?

Finnish is a pro-drop language, meaning that the personal pronoun (in this case minä, “I”) can be omitted because the verb form already indicates who the subject is. Tarvitsen already tells us that "I need” because of the personal ending -n in the verb.

Can nyt appear somewhere else in the sentence, and would it still be correct?

Yes, you could say Nyt tarvitsen vettä or Tarvitsen nyt vettä, and it would still make sense. However, the emphasis might shift slightly. Placing nyt at the beginning emphasizes now, while keeping it at the end makes it simply an additional detail.

Is it common to pronounce the sentence more quickly or blend words together in everyday speech?