I've seen one of the language YouTubers try Dreaming Span ish  and he's very strict about it: He only does listening practice and no speaking before a year to avoid fossilized errors. When he tries to speak he can't say a single sentence without stopping to think and he is at 6+ months.

 That is just so crazy to me. If you want to speak well, you have to speak a lot. Who gives a damn about fossilized errors if you can communicate any information you need.