kolektiva

A seam that is not there. Kolektiva looks like kolekti plus -iv- plus -a, and that reading almost works, which is what makes it a trap. It does not mean having the capacity to collect. It means belonging to a group, and it arrived from Latin collectivus in one piece, the way aktiva, alternativo, motivo and naiva did. The -iv in the middle is a dead Latin suffix riding inside a borrowed root: packaging, not a joint.

The honest version of the rule. Older notes on this site said flatly that Esperanto has no -iv- suffix. That went one step too far, and the article on the unofficial affixes sets it out properly: the Reta Vortaro does carry -iv/ as a headword, labelled an unofficial suffix for active capability, set against the Fundamental -ebl- for passive capability. Kreiva, produktiva, informiva are real formations. What is true is the narrower thing: kolektiva is not one of them. Recognise the suffix when you read it, do not coin with it, and never cut a borrowed root apart to find it.

Where it earns its keep. Esperanto is a movement language and the movement does a great deal collectively: kolektiva decido, kolektiva letero, kolektiva laboro, kolektiva respondeco. The noun kolektivo is a collective in the organisational sense. Against it stands the individuo at 1,809, and beside it komuna at 657, which is the everyday word for shared: a komuna kuirejo is shared by the flat, a kolektiva decido was taken by the whole body acting as one.