What kind of bullshit is this?, I am fluent in 4 languages yet I speak to my son in my mother tongue, not because I don't speak the other languages good enough, in fact, the only time I get to use my mother tongue is at home with my kid, you tent to speak to your kids in your mother tongue because it comes natural plus you are giving them an extra language for free (if you live in a different country where a different language is spoken)
Parents who don't teach/pass along their mother tongue to their kids just because they live in another country are making a huge mistake, kids will pick-up whatever the official language is at school, your mother tongue however might be lost forever or will become increasingly hard to learn as kids grow up.
My 2 and a half years old son speaks spanish to me and switches to german right away when speaking to his mom (my wife is german), that's 2 extra languages he'll have besides the 2 official ones from here (we live in Montreal), he just started daycare in french and his teacher already told me he understands a lot and he had begun to repeat and say some words in french.
not to shabby for a 2 and half years old