The concept of comparisons and superlatives are (probably) the same as any language where things can be compared to one another, while using a superlative can be used to describe the highest degree of something. For example, the comparison of the adjective big is bigger, while the superlative is biggest.
Whether adjective or adverbs, comparisons and superlatives typically have strong KPT stems, followed by the appropriate ending suffix being added.
Adjectives are words that describe other words. As is the case with many Finnish words, the adjective rules for comparisons and superlatives are typically tied to how many syllables a word has, what the ending vowel is, whether or not the word is an old or new Finnish word, and so forth.
After following the KPT rule the ending suffix of -mpi or -in is added for adjective comparisons and superlatives respectively.
Some examples can be found below, and a fuller list of adjectives can be found here.
More information about adjective comparisons can be found from the following links:
- Komparatiivi ja Superlatiivi @ The Finnish Teacher
- The three degrees of comparison for Finnish adjectives @ Finking Cap