Debate: A global language or national languages?

English

http://www.englishlanguageguide.com/english/facts/stats/ 

http://www.framtak.com/english/facts.html -

http://www.learnenglishguide.com/english/language/whyenglish.asp -

http://englishenglish.com/english_facts.htm -

http://www.how-to-learn-languages.net/2009-05-10-reasons-to-learn-english.php -

Spanish

http://spanish.about.com/od/historyofspanish/a/10_facts_about_spanish.htm- 

http://www.spanish-fiestas.com/language/spanish-language-facts.htm- 

http://www.spanish-school.com.mx/learnspanish.php- 

http://www.learnspanishguide.com/spanish/language/whyspanish.asp- 

Esperanto

http://www.micheloud.com/FXM/la/la/esperanto.htm- 

http://www.language-learning-advisor.com/learning-esperanto.html- 

http://news.bbc.co.uk/2/hi/uk_news/magazine/7505820.stm- 

http://edufire.com/content/articles/95-top-10-reasons-to-learn-esperanto- 

http://www.esperanto-usa.org/en/content/getting-started-learning-esperanto- 

Mandarin

http://ezinearticles.com/?10-Reasons-to-Learn-Mandarin-Chinese&id=1843502- http://ezinearticles.com/?Learn-Mandarin---3-Reasons-Why&id=5301588 –

http://mandarin.about.com/od/chineseculture/a/why_learn.htm- 

http://www.articlesfactory.com/articles/education/top-10-reasons-to-learn-mandarin-chinese.html

http://www.downloadalanguage.com/downloadalanguage/Reasons_to_learn_Chinese.html 

Portuguese

http://www.eu-student.eu/why-you-should-learn-portuguese/

http://lusophoneworld.blogspot.com/2008/11/top-reasons-to-learn-portuguese.html

http://www.micheloud.com/FXM/la/la/portuguese.htm

http://ezinearticles.com/?3-Reasons-to-Learn-Portuguese&id=5219484

http://www.sjsu.edu/foreignlanguages/programs/undergraduate/portuguese/

National languages

http://www.languageiseverything.com/language-translation-services/images/Which_language.pdf

http://www.onlinecollege.org/2010/07/26/50-reasons-you-should-learn-a-new-language/

http://www.vistawide.com/languages/why_languages.htm

http://www.adfl.org/resources/knowing_other_languages.htm

http://www.language-learning-advisor.com/why-learn-languages.html