Learn Hardcore Finnish: Kova pakkanen estää meitä uimasta järvessä. - The severe frost prevents us from swimming in the lake.

The verb estää (“to prevent/stop”) takes its direct object in the partitive when you’re talking about an incomplete or ongoing action. Here, meitä is the partitive plural of me – “us.” Using meidät (the accusative) would imply a completed, bounded action (“you prevented us entirely”), but since you’re preventing us from doing something (swimming), the partitive meitä is correct.

Why is the verb uimasta not the basic infinitive uida?

Finnish uses the so-called “–mA” infinitive plus a case ending to express “from doing” something.
• The –mA infinitive (sometimes called the third infinitive stem) turns uida into uima-.
• Adding the elative ending –sta gives uimasta, literally “from (the act of) swimming.”
So the construction estää + [object in partitive] + [–mA infinitive in –sta] means “prevent someone from doing something.”

What case is järvessä, and why is it used here?

Järvessä is in the inessive case (indicated by –ssä) and means “in the lake.” Finnish doesn’t use prepositions like “in”; instead, location “inside” something is shown by the inessive. Since the swimming would take place inside the lake, järvessä is the correct choice.

How does the structure estää meitä uimasta work in Finnish?

The pattern is:
estää (verb) + object (in partitive) + infinitive (–mA + case)
That is, estää meitä uimasta = “prevent us from swimming.”
You can slot in other objects and actions the same way:
Estä pientä lasta juoksemasta (“Prevent the small child from running.”)

What does kova pakkanen mean literally, and why is kova used?

Literally, kova pakkanen is “hard frost.” In practice it means “severe frost” or “bitterly cold weather.” Kova is an adjective meaning “hard,” “strong,” or “severe,” modifying pakkanen (“frost/cold”) to emphasize that the cold is intense.

Could we rephrase the sentence without meitä by using a noun instead of the infinitive?

Yes. You can replace the verb phrase meitä uimasta with the verbal noun uiminen (“swimming”) and say:
Kova pakkanen estää uimisen järvessä.
This means “Severe frost prevents swimming in the lake.” It’s more general (no specific “us”), but grammatically it works.

What are the morphemes in uimasta, and what do they each mean?

Breakdown of uimasta:
• uima-: the stem of the –mA infinitive derived from uida (“to swim”)
• –sta: the elative case ending meaning “out of/from”
Together, uimasta literally means “from the act of swimming,” which in English we render “from swimming.”