Learn Finnish: Koira löytää minut.

minut is the accusative form of the personal pronoun minä (I). You use this form when an action is fully completed. Since the dog successfully finds you, you are the total object of the action, so you use minut. If the dog were only looking for you (an ongoing action), you would use the partitive form minua.

Why does the verb löytää end with a double ä?

This is the third-person singular form, matching the subject koira (the dog). For many Finnish verbs, you create the "he/she/it" form by taking the verb stem and doubling its final vowel. The stem here is löytä-, so doubling the final ä gives us löytää.

Do all personal pronouns get a -t at the end when they are the object?

Yes, when a personal pronoun is the total object of a completed action, it gets a -t ending. Just like minä becomes minut, sinä (you) becomes sinut, and hän (he/she) becomes hänet. This is a special rule just for personal pronouns and the word kuka (who).

Could I change the word order and say Minut löytää koira?