2021-04-16 : Any cards exiled with Ardent Dustspeaker that you don’t play remain exiled. You will not be able to play them on later turns, even if Ardent Dustspeaker’s ability triggers again.

2021-04-16 : Playing the cards exiled with Ardent Dustspeaker follows the normal rules for playing those cards. You must pay their costs, if any, and you must follow all applicable timing rules. For example, if one of the cards is a creature card, you can cast that card by paying its mana cost only during your main phase while the stack is empty.

2021-04-16 : The cards exiled by Ardent Dustspeaker’s ability are exiled face up.

2021-04-16 : Unless an effect allows you to play additional lands that turn, you can play land cards exiled with Ardent Dustspeaker only if you haven’t played a land yet that turn. In most cases, if you exile two land cards, you won’t be able to play both.

2021-04-16 : You may play those cards that turn even if Ardent Dustspeaker leaves the battlefield or another player gains control of it.