Learn Dutch: Die blauwe pet, die vind ik erg sportief. - That blue cap, I find it very sporty.

This is a great example of 'left dislocation' to emphasize a topic. We pull the thing we want to focus on (Die blauwe pet) completely to the left, outside the main clause. The second die is a demonstrative pronoun that points back to the cap and acts as the grammatical object of the sentence. Literally, you are saying: 'That blue cap, that find I very sporty.'

Why does the verb vind come before the subject ik?

This happens because of the strict V2 (verb second) rule. The isolated phrase at the beginning (Die blauwe pet) sits outside the main clause and doesn't count as position 1. The main clause actually starts with the second die (position 1). The verb vind must take position 2, which forces the subject ik to come right after it.

How would this sentence change if we used a neuter word, like het shirt, instead of de pet?

Since shirt is a het word, both demonstrative pronouns would change from die to dat. The sentence would be: Dat blauwe shirt, dat vind ik erg sportief.

I know sportief means athletic for a person, but is it normal to use it for an object like a cap?

Yes, absolutely. When describing clothing, shoes, or accessories, sportief means 'sporty' or 'casual-looking.' It's a very common way to compliment someone's everyday, active-style outfit in Dutch.