Learn #Esperanto with me! Today it's the words of the family. #conlang #learnesperanto

What does the suffix “-in-” mean in Esperanto?

Teaching family vocabulary, this clip states the rule directly: “if you add -in- at the end of the word, you get the feminine word.” Onklo (uncle) becomes onklino (aunt), and the same pattern gives Esperanto’s most common family pairs — patro/patrino (father/mother), frato/fratino (brother/sister) — from a single masculine-default root plus one inserted syllable.

The pattern is powerful but not gender-neutral by default: unlike occupational words such as instruisto (teacher), which many speakers now treat as gender-unmarked, these family roots really do assume male unless -in- is added — viro (man) and virino (woman) work the same way. It’s a known asymmetry in the language, and one reform proposals have targeted for over a century, without displacing the pattern in everyday use.