Why talk Greek n Latin?

One of the most annoying thing which I have noticed in a multi cultural work atmosphere is people talking in a language with zero consideration for the other people around who don't understand the language that is spoken. Most of the times the language happens to be the mother tongue of the majority of the people in that group.
Initially I used to think, only I used to feel abased. But when I discuss about this to many people, I understand many people find it very uncomfortable when the people around them talk in some language which they dont understand. I had my first experience of this when I was working in Karnataka. I experienced this many times when I was with a malayalee gang. So I started avoiding to go along with any malayalee gang after that. But later faced the same with some north Indian colleagues too. My sister used to complain about the people from Andra who talk in Telugu, without considering that there is a person with them who does not understand their language. Then a Telugu friend of mine used to complain to me about tamilians who talk in Tamil even though they knew that there were some non tamil speaking people in the group. So I realised people irrespective of where they come from everyone faces this problem and do nothing but point their fingers at some group or the other. They don't think that even they might be doing the same to someone else.
Another common thing that I have noticed on this front is, say if two tamilians discuss about this issue, then they tend to boast that their community (community I mean people who speak the same language) are not like that and they always consider the other people and talk in a common language. Similarly Marathi, Gujarathi, Telugu, Malayalee, Kanadiga, Bengali etc.. also boast about their community. In reality none of them have any consideration for the other community people when they are in majority.
Is'nt it a basic courtesy to talk in a common language and common subject so that everyone in the group can enjoy what others are enjoying? Why is it that we fail to do it? Why don't we think of others by being in their shoes?
On a different note, A tamil speaking man was interogated at Seatle since a off-duty airport authority suspected him and alerted the flight crew. Click here to read the news article on The Hindu.

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