Definition from Wiktionary, a free dictionary

Finnish

Etymology

Derived from the noun kieli (“‘tongue, language’”) by adding adjectival suffix -inen.

Adjective

-kielinen (stem -kieli-^*) (comparative -kielisempi, superlative -kielisin)

1. (not comparable) Being of a language.

   kaksikielinen — bilingual

2. -tongued.

   pitkäkielinen — long-tongued

Usage notes

In Finnish the names of languages are usually either the same as that of the country or a geographic area where the language is spoken, only with a small initial letter:

• France -> French = Ranska -> ranska (or, to avoid confusion, ranskan kieli)
• England -> English = Englanti -> englanti (id., englannin kieli)

or (like in English) same as the word referring to a member of the nation, tribe, etc. that speaks the language:

• Aztec -> Aztec = atsteekki -> atsteekki (id., atsteekin kieli).

Any name of a language can be combined with the adjective -kielinen to produce an adjective which refers to that particular language:

• englanti -> englanninkielinen = English (English-language)

Note that the name of the language is in genitive. The word kielinen cannot be used alone.