Interesting question. I've had two foreign trips this year. One to the united Arab Emirates and one to Israel. In both cases I was keen to learn some basic phrases of Arabic and Hebrew respectively. But despite these intentions I didn't need to know a thing. English appeared to be ubiquitous. So practically speaking it seems that there isn't a great deal of need.

Though in my opinion, knowing another language is a matter of respect to some extent. Just to be aware that there's another world out there.

So one way in which their educational development might be damaged is in their world view. Doubtless there is also a value in using the brain in a different ways. I remember being told that Latin was an important language (though no one speaks it). I now see that it was the only subject in which I learnt about grammar - though I remember nothing of it. There is also a certain logic to the way language fits together which could be applicable in other subjects areas of life I imagine.

As to which language and why: for sheer quantity of speakers and potential discoursees (?), you would imagine Chinese or Spanish would be important. Though every language has it's only satisfaction and beauty I expect so diversity might be great thing. Especially if we think of language and its insights into mentality, etc.

Hi,

The response is both "yes and no'. No, because the Brits used to be powerful enough to assume one of the world powers. This is how they spread their culture and language throughout the world. English turned into an international language that many people in the world felt necessary to learn. However, today, there are other factors that highlight the importance of learning English (political, economic, technological, etc.) That English is now widely used all over the world as a lingua franca does exclude the need for the Brits to learn foreign languages. On the other hand, the answer is positive. It is traditionally believed that language learning improves one's mind and cognition (mental processes). In the technological era and communication, mobility takes place easily and fast. The Brits migrate to other countries of the world. To feel empathy with other nationals, they would need to learn other languages as well. 

Just thought it'd be interested to add a comment on this topic from the Pearson Facebook page:

No, learning too many foreign languages is a waste of time. Speaking from experience.

.. and money.

http://www.facebook.com/PearsonELT#!/PearsonELT/posts/289322207830991?comment_id=1359104&offset=0&total_comments=2

I suppose practically speaking she has a point.