Learn Swedish: Skidåkaren tävlar och tränar flitigt. - The skier competes and trains diligently.

This lesson is about comparative and superlative adverbs. How would I change flitigt to say the skier trains "more diligently" or "most diligently"?

For regular adverbs like flitigt, you form the comparative by adding -are to the base adjective (flitig becomes flitigare). For the superlative, you add -ast (flitigast). So, "more diligently" is flitigare and "most diligently" is flitigast.

Why is there a -t at the end of flitigt? Doesn't that mean it's an "ett" word?

Not in this case! Here, flitigt is an adverb, because it describes how the skier competes and trains (which are verbs). In Swedish, you create regular adverbs by taking the adjective (flitig) and adding a -t. It looks exactly like a neuter (ett-word) adjective, but it acts as an adverb here.

Why is "the skier" written as skidåkaren instead of skidåkareen?

The base noun for "skier" is skidåkare. En-words that already end in -are (which are usually professions or people who do a specific action) just add an -n in the definite "the" form. This stops the word from having an awkward double "e".

Skidåkare is quite a long word. What are its smaller parts?