- intentionally making your kid deaf - like some deaf people want to do, arguing it will help the child experience deaf culture;
- raising a child in an unpopular language - like most parents speaking unpopular languages do, arguing it will help the child experience that language's culture.
I've expressed this sentiment in the past: languages with small numbers of speakers, like Slovenian, are poison for the people brought up speaking them. It should be a basic human right that one should be not just taught, but raised in a major world language, one that's e.g. in at least top 10 by total number of speakers. Of those, it should possibly not be a language spoken by a monoculture, but an international language that enables conversation with people from a wide number of countries.
If you raise your kid in a small language, and only make a token effort of teaching an international one, it's as if you are intellectually disabling your kid, preventing or impeding him or her from accessing the vast majority of knowledge and ideas that would otherwise be easily accessible.
The only acceptable way to speak a small language should be to be fully bilingual, maintaining equal fluency in an international language. When a child cannot be raised fluently in two languages, an international language should take precedence over a small one.