perusteilla

Perusteilla is a Finnish adverb formed from the noun peruste, meaning basis or foundation, with the locative suffix -lla. It roughly translates to “on the basis of” or “on the grounds of” and is used to indicate that a statement, decision, or action rests on a particular source, evidence, or set of circumstances. The form is most common in formal or written Finnish, such as policy documents, legal texts, and academic writing. In everyday speech, speakers typically use phrases like perustan mukaan or pohjautuen to express the same idea.

Usage and nuance: Perusteilla typically introduces the grounds for a claim or conclusion. It can appear in noun phrases or clauses, often in contexts where the reliability or relevance of information is being referenced. For example, one might encounter constructions such as perusteilla olevien selvitysten mukaan or perusteilla olevan hankkeen perusteella, meaning “according to the investigations that exist” or “based on the ongoing project.” While clear, the phrase can feel somewhat formal and is not as common in casual conversation.

Relation to related expressions: Other common ways to express the same idea include perusteen mukaan (according to the basis) and pohjautuen (based on). These alternatives may be preferable when aiming for simpler or more conversational Finnish. Perusteilla shares its core meaning with these expressions but carries a stronger locational sense of being “on a basis.”

See also: peruste, perustelu, perusteellinen, pohja, pohjalta.