Minnesota's former native speaker of Klingon

The story about perhaps the world's only (former) native speaker of Klingon has made a bit of news again, as it tends to from time to time given the eccentricity of the subject. A bit over a decade ago a father and his son made news as he had been speaking only Klingon to his son for the first three years of his life, and thus he was at the time (since he's probably forgotten most of it now) the only native speaker of Klingon in the world. A later article from 1999 goes over some of the difficulties the "project" had, such as lack of vocabulary for common concepts and simple boredom.

Ironically, teaching one's child a language like Klingon in this way could theoretically be one of the surest ways to guarantee a future career, as Star Trek conventions are big business and being a native speaker would result in guaranteed paid gigs talking about one's life as a fluent speaker of Klingon. Whether that would be a fun way to make a living or not would depend on the person.

Just teaching one's child a made-up language with no relation to anything else though would be doing a disservice, unless evidence surfaces that a language like Ithkuil actually improves human cognition, in which case it would be no worse than having one's child do any other number of mental puzzles and tasks that parents are often such fans of.

The best "artificial" language to teach to a child though would either be one with a community (Esperanto/Ido/Interlingua), a reconstructed or revived one (Latin/Modern Indo-European), or one with enough similarities to other languages that having the language as a mother tongue would actually serve a purpose later on even if the child abandons it (Occidental/Novial/Lingua Franca Nova/etc.). Out of these, Latin and Modern Indo-European would probably be the best at guaranteeing a future career path, since both of these have strong academic backing and would be similar to Klingon in the guest appearances and collaboration with translators and researchers one could make. Lojban is perhaps a bit iffier, but it does have a community that doesn't seem to be in any danger of dying.

Teaching one of these languages though is not a bad thing - many would call it a type of child abuse, but it's certainly not as long as it isn't forced (the Klingon dad gave up on the idea when his son began to get bored, so no problem there). In fact, the amount of parent-child interaction required to teach a language in this manner is quite huge, and spending that much time with one's mom or dad playing and conversing is a very good thing, especially compared to the large numbers of children who spend the day being babysat by the TV.

For a short clip (a trailer from a documentary on Klingon) featuring the dad, see here.