Yes. In my opinion, entirely. I'm also a believer that how one chooses to speak impacts their behavior and ultimately how they think (of themselves and others).

Yes. In my opinion, entirely. I'm also a believer that how one chooses to speak impacts their behavior and ultimately how they think (of themselves and others). People who speak negatively tend to be negative people. I find the opposite to be true as well, as long as the speech is genuine. Someone "faking" their optimism could of course be a really negative person, regardless of how they speak. I think believing what you say plays a big role. I find myself complimenting others and thanking people for things more frequently in Japanese. Not just as a formality - but because it seems so much more natural than in English. And I think it is very important that any person who speaks only one language does their best to embrace another culture and learn a second. It will change how you think about many things.