sa-insertion word; extra-sa causative form
Linguistic term for non-standard causative forms where an extra さ is inserted, e.g. 行かさせる instead of standard 行かせる. Often considered a grammatical error or dialectal variant.
Saying 食べさして instead of 食べさせて is an example of sa-insertion.
In Japanese language education, sa-insertion words are often treated as errors.