I looked for some language exchange partners, and discovered many Europeans can speak more than 2 kinds of languages. You can speak so many languages beacause you really like learning language or other reasons? How long do you spend on learning language everyday？How do you learn a new language?
Location. Location. Location.
In the USA and Canada there is little need to go beyond English but in Europe each country is surrounded by, or close to different language speaking countries. So it behooves you to learn a second or third language if you wish to meander beyond your borders.
Since Europe(specifically the European Union) has so many languages, it is very useful to know how to speak more than one of them for job purposes. Also, there are European countries that have more than one official language, like Belgium for example.
Being from the UK, I speak English, a little Spanish and a little French, as well as basic German. French and German are taught at our secondary schools (aged 11-16), and Spanish is usually encouraged and primary schools (aged 4-11). At secondary school we have to take either French or German as a subject for 3 years, we don't get a choice, but in the long run it makes it better as it improves our chances of getting a job or univerisity place etc.
Europe is a very small continent. Many nations are landlocked regardless of the direction one might travel. Many citizens of one nation would relocate to a neighboring nation and cultural diffusion would occur. Thus it would not be out of the ordinary for a European to learn more than one language.
I think they must be like that or due to some reason such as they like other country culture and maybe some work reason