Where does “cortesissimo” come from?

cortesissimo (Italian) comes from Italian -issimo, from Latin -issimus, from Proto-Italic *-isəmos — forms superlative forms of adjectives.

Ancestry of “cortesissimo”, step by step

StepLanguageWordMeaning
1Italian-issimoAdded to adjectives to form superlatives; Added...
2Latin-issimusadded to an adjective noun to form its...
3Proto-Italic*-isəmosforms superlative forms of adjectives
Every word from Proto-Italic *-isəmos →Every word from Italian -issimo →Every word from Latin -issimus →