Learn Finnish: Minä istun saunassa. - I am sitting in the sauna.

We take the base word sauna and add the ending -ssa, which means "in". Because sauna is a simple word that doesn't change its stem, we just attach the ending directly to the end.

Why is the ending -ssa instead of -ssä?

This is because of vowel harmony. Finnish words generally can't mix back vowels (a, o, u) with front vowels (ä, ö, y). Since sauna contains the back vowels a and u, the ending must also use a back vowel. Therefore, we use -ssa.

Does istun translate to "I sit" or "I am sitting"?

It translates to both! Finnish doesn't have a separate continuous form like English does with "am sitting". Depending on the context, istun can mean "I sit" as a general habit, or "I am sitting" right now.

Can I leave out the word minä and just say Istun saunassa?

Yes, you can. The -n at the end of istun already tells us that "I" am the one sitting. In everyday Finnish, it is very common to drop the words for "I" (minä) and "you" (sinä).