Is this a bad attitude?

Ever since I was a kid, I always try to keep my
conversations in private although I was in a public
place. How?

Well, I speak English, Cantonese, Hockkien,
Chinese and Malay/Indonesian. So, I guess I have
many choices to keep my dialogue safe huh.

Sometimes, it is bad to speak a language that
no one understands if u are among your friends.
If everyone knows everyone, I feel it is all right.

This British and this American are in Malaysia
and one of them ask, What are those guys
speaking? The other replied, They are speaking
English.

I wondered if there is a poster or something
about the evolution of language.