What is the meaning of -si?

Alternative form of -i

indicates that something is indefinite or uncertain

Clitic form of se (oneself)

Romanization of ᠊ᠰᡳ

her

you

his

Second-person singular possessive suffix used with or without sinun (the genitive form of the personal pronoun sinä): your sg, thy

Appended to a genitive-requiring postposition that is after or without sinun: you sg, thee

Used in a participle structure replacing an että clause, preceded by a verb expressing e.g. telling, claiming, asserting, confirming, thinking, wish, desire, seeming, when the clauses have the same subject "you" (addressing one person); appended to the active present participle in genitive singular when the action is concurrent with the main clause.

Used in a participle structure replacing an että clause, preceded by a verb expressing e.g. telling, claiming, asserting, confirming, thinking, wish, desire, seeming, when the clauses have the same subject "you" (addressing one person); appended to the active past participle in genitive singular when the said/alleged (etc.) action antedates the main clause.

Used in a shortened sentence expressing concurrent actions when the clauses have the same subject "you" (addressing one person), appended to the inessive of the active second infinitive.

Used in a shortened sentence expressing subsequent actions when the clauses have the same subject "you" (addressing one person), appended to the partitive of the passive past participle singular.

Used in a final shortened sentence expressing "in order to do" when the clauses have the same subject "you" (addressing one person), appended to the long first infinitive.

Used in some adverbs, when the clause has the subject "you" (addressing one person).

Always appended to a noun in the comitative case when the clause has the subject "you" (addressing one person).

Synonym of -i

Added to a noun to form an adjective expressing “belonging somewhere, originating from, coming from”.

Added to a shortened noun to form a new diminutive noun.

-tion

Alternative form of si

inflection of -sus:

  1. nominative/vocative masculine plural
  2. genitive masculine/neuter singular

nominative/vocative masculine plural

genitive masculine/neuter singular

-tion; -sion.

-cy.

Evidential suffix, second-hand information. Indicates that the speaker has not directly experienced the information at hand; hearsay

-like, -ish, -ly (It derives adjectives)

Alternative form of -ki

third-person singular possessive suffix, used after a noun ending in a vowel

Source: wiktionary.org