That’s the catchphrase from a TV commercial for the Rosetta Stone language learning software that’s been playing over here for a few weeks now.
Gaikokugo-ga bokokugo-ni naru: “a foreign language will become your native language (lit., mother language).”
The commercial itself is kinda fun, starring a cute little bappa whose Aomori dialect is thick enough to necessitate subtitles in the standard language. Just as she is telling you about how they’ve started getting orders for their apples from Brazil, the phone rings and, guess what, she starts talking in Portuguese. You eventually get to see her sitting in front of the PC using the software to study, and after the pitch the “CM” ends with the catchphrase.
Since I speak neither Aomori-ben nor Brazilian Portuguese, I can’t say how good she speaks either, but I imagine the actress has an interesting story or two to tell.
I also haven’t spent enough time in the States recently to know what kind of ads Rosetta Stone runs there, but I can only assume that they aren’t as silly or immoderate in their claims (past a certain age, a person will not be able to replace their native language with a foreign one) as this Japanese one is.