Learn Hardcore Icelandic: Fyrirtækið mitt er lítið.

Because fyrirtæki is a neuter noun, and Icelandic marks definiteness with a suffixed article. Neuter nominative singular definite is -ið, so fyrirtæki (a company) becomes fyrirtækið (the company).

Why do we have both the definite ending and the possessive mitt?

When a possessive pronoun comes after the noun, Icelandic normally adds the definite suffix to the noun: fyrirtækið mitt (literally “the company my”). If you put the possessive before the noun, you do not add the suffix: mitt fyrirtæki. Both mean “my company”; postposed is the neutral default, while preposed is a bit more contrastive or emphatic. Avoid fyrirtæki mitt without -ið in this structure.

Can I say Mitt fyrirtæki er lítið instead?

Yes. That is correct and common. It’s slightly more contrastive (highlighting “my”), whereas Fyrirtækið mitt er lítið is the neutral default.

Why is the adjective lítið ending in -t?

Agreement. The adjective lítill (small) has nominative singular forms: masculine lítill, feminine lítil, neuter lítið. Because fyrirtækið is neuter singular, the predicative adjective must be lítið.

Do adjectives have to agree with the subject after ?