The Additive Clitic -kin
To say "also" or "too" in Finnish, you don't typically use a separate word. Instead, you attach the clitic -kin directly to the end of the word you want to emphasize or add to.
When you attach -kin to a noun or a pronoun, it always goes at the very end of the word, after any case endings. For example, me (we) becomes mekin (we also), and heillä (they have) becomes heilläkin (they also have).
Notice how it attaches after the partitive case ending in minua (me) to become minuakin:
You can also attach it to demonstrative pronouns like tuo (that) or tämä (this):
Finding Common Ground
Using -kin is a great way to share opinions, agree with others, and talk about shared interests. To express that you agree with someone, use the phrase olla samaa mieltä (to be of the same opinion).
You will frequently encounter the word tietenkin (of course). It is a fixed word that already contains the -kin suffix.
Finally, you can even attach -kin directly to a verb. This emphasizes that an action also happens, in addition to something else.