Nukkuessaan
Nukkuessaan is a Finnish adverbial participle form of the verb nukkua (to sleep). It conveys that an action occurred at the same time as the action described in the main clause, roughly translating to "while he/she was sleeping" or "as he/she slept." The form is typically used to set background circumstances in narrative or descriptive text.
Formation and usage: Nukkuessaan is built from the verb stem nukkua plus the suffix -essaan, which marks
Grammatical notes: The -essaan form belongs to a family of adverbial participles in Finnish that express simultaneity
See also: Finnish participles, adverbial participles, and related forms such as nukkuessa (present-time sleeping) and kävellessään