Questions & Answers about Pidempi häntä on parempi.
Why is the word for "better" parempi when the word for "good" is hyvä?
Just like in English (good/better), the comparative form of hyvä is completely irregular. It changes to parempi (better), and its superlative form is paras (best).
How do we get pidempi from pitkä (long)?
Pitkä is an irregular adjective. When forming the comparative, the -tkä ending drops and is replaced by -dempi. So, pitkä becomes pidempi (longer).
Why are pidempi and parempi in the basic nominative case here instead of the partitive?
The subject of the sentence is häntä (a countable singular noun, meaning tail). Because of this, both the adjective attached to it (pidempi) and the adjective describing it after the verb (parempi) stay in the nominative case.
Could I say Häntä on pidempi ja parempi instead?
You could, but it changes the meaning slightly. Pidempi häntä on parempi means "A longer tail is better", focusing on a general preference. Häntä on pidempi ja parempi means "The tail is longer and better", describing one specific tail.