I am interested in finding out if any Latin enthusiasts speak Latin to their children, so that the children grow up with Latin as one of their native languages. If yes, can any description of their experience with this endeavour be found online?
I know of five kids who are growing up speaking Latin, and I imagine there have to be more that I don't know about. One is Josiah Meadows, who does online spoken Latin lessons himself. You can see him in several YouTube videos here. Another is the now 2-year-old son of an American who lives in (or perhaps not far from) Rome. Two are the kids or stepkids or adopted kids of Patrick Owens, who now curates the Morgan Lexicon; I've met one of them. And the fifth is a boy whose name I can't remember but I met him a few weeks ago at the Conventiculum in Kentucky. They all started Latin before the critical age (that is, the age at which language-learning flips from being unconscious to being conscious), which is about 12.
I'm confident that you could write Josiah or his father Scott (I've never met or communicated with either one of them, but they've both talked online and with newspapers/websites about Josiah's experience) and ask them further questions.