Learn Finnish: Kysyisin tästä foorumista. - I would ask about this forum.

The verb kysyä (to ask) governs the elative case (-sta / -stä) when you are asking about something. Cognitive verbs related to talking, thinking, or having an opinion often use the elative to express the subject matter. So, foorumista literally gives us "about the forum."

Why did the word tämä (this) change to tästä?

In Finnish, modifiers like demonstrative pronouns must match the grammatical case of the noun they describe. Since the noun is in the elative case (foorumista), the pronoun tämä must also take the elative ending, becoming tästä.

What part of kysyisin makes it "I would ask" instead of just "I ask"?

The -isi- in the middle of the word is the conditional marker, which translates to "would" in English. Added to the verb stem of kysyä along with the first-person -n ending, it becomes kysyisin. Finns frequently use the conditional mood at the start of a conversation to make a request or question sound softer and more polite.

If I wanted to direct my question to the forum, would I still say tästä foorumista?