portaisiin

Portaisiin is a Finnish grammatical form used to express movement into multiple stairs or stairwells. It represents the illative plural, a case that marks direction toward a destination, in this instance toward several stairs. The form illustrates how Finnish uses suffixal changes to indicate number and grammatical case, with illative plural endings often appearing as -iin in nouns that take the -iin pattern in the plural.

In terms of usage, portaisiin tends to appear in descriptive or architectural writing, navigation descriptions, or literary contexts where the speaker or narrator refers to entering more than one flight of stairs. It is less common in everyday speech, where speakers might simplify the construction or rely on context rather than explicitly invoking the plural illative.

Grammatical notes include that Finnish illative forms vary by noun stem and sometimes by phonological adjustments such as vowel harmony and consonant gradation. Portaisiin is one of several plural illative examples, illustrating how plural destination is encoded in Finnish. It is related to other stair-related terms such as portaali (portal) and portaat (stairs), helping to differentiate movements toward different kinds of vertical access in descriptive text.

See also: Finnish grammar, illative case, portaat, portaali.