Comparatives in cases (-mpa-/-mma-)

Comparative adjectives end in -mpi in their basic form (e.g., isompi, parempi). When inflected in other grammatical cases, the stem changes to either -mma- / -mmä- (weak) or -mpa- / -mpä- (strong).

The Weak Stem: -mma- / -mmä-

If the case ending closes the syllable (usually because it ends in a consonant), the stem weakens to -mma- / -mmä-. This applies to cases like the Genitive (-n), Inessive (-ssa / -ssä), Elative (-sta / -stä), and Adessive (-lla / -llä).

Adjectives must agree with the nouns they modify, so both the comparative adjective and the noun take the exact same case ending:

The Strong Stem: -mpa- / -mpä-

If the case ending leaves the syllable open (typically a vowel or ending in a vowel), the stem stays strong as -mpa- / -mpä-. This mainly applies to the Partitive (-a / -ä) and the Illative (-an / -än).

Note: In the partitive case, the final vowel of the stem simply doubles (e.g., -mpa- + -a = -mpaa).

Bringing It All Together

When evaluating product specifications, you will frequently need to string multiple features and comparatives together. As long as you match the case of the noun to the case of its adjective, you can build highly descriptive, complex comparisons.