What are the five most common languages in the world?
I've trying to find the answer, but there's been so many result. 
Please help me. Would you let me know the searching-information strategy?
Thanks

Qtue

Hi Qtue,

THank you for your question.


Time for Kids Classroom
http://www.timeforkids.com/TFK/class/ns/article/0,17585,186570,00.htmlSource 

Top 5 Languages of the World - Source TIME Almanac 2001

1. Mandarin Chinese: 885 million

2. Spanish: 332 million

3. English: 322 million

4. Bengali: 189 million

5. Hindi: 182 million

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The Most Common Languages in the World
http://anthro.palomar.edu/language/language_1.htm

Mandarin Chinese is the most common, being spoken by around
874,000,000 people as a native language.  English is a distant third
with approximately 341,000,000 native speakers.

Language  ----  Approx. number of native speakers year 2000

1. Mandarin Chinese ---------       874,000,000  
2. Hindi (India) ------------       366,000,000   
3. English ------------------       341,000,000 104 
4. Spanish ------------------       322-358,000,000   
5. Bengali (India and Bangladesh)-- 207,000,000    
     
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The World's Most Widely Spoken Languages
http://www2.ignatius.edu/faculty/turner/languages.htm

The Summer Institute for Linguistics (SIL) Ethnologue Survey (1999)
lists the following as the top languages by population:
(number of native speakers in parentheses)

 1.  Chinese* (937,132,000) 
 2.  Spanish (332,000,000) 
 3.  English (322,000,000) 
 4.  Bengali (189,000,000) 
 5.  Hindi/Urdu (182,000,000) 
 6.  Arabic* (174,950,000) 
 7.  Portuguese (170,000,000) 
 8.  Russian (170,000,000) 
 9.  Japanese (125,000,000) 
10.  German (98,000,000) 
11.  French* (79,572,000) 

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SEARCH STRATEGY

most common languages in the world
top five languages of the world
top 5 languages of the world

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Best regards,
tlspiegel

Those numbers are counting native speakers, which is fine.  English is
spoken as as second language by a great many people, not only by many
Europeans but also many Indians, and there are a billion or so of
them.  So this site's figure of more than 750 million may not be far
off:

http://www.englishenglish.com/english_facts_5.htm

Yes, the site quoted in the answer
http://www2.ignatius.edu/faculty/turner/languages.htm has interesting
figures counting secondary speakers and also number of countries in
which a language is spoken, further down the page from the stats
quoted in the answer.  I already posted a comment mentioning this, but
it's been deleted.  I'm a bit taken aback as the comment didn't have
anything contentious in it or any abuse or anything.

Brazil alone has about 185 million Portuguese speakers. Then you have
Portugal with another 10 million, Angola, Mozambique, Timor, Macau,
São Tomé e Príncipe, Guiné Bissau, Cabo Verde, some parts of India,
and several million portuguese emigrants in other countries. Galego
(spoken in the north of Spain) is also considered as a portuguese
dialect by most linguists. I am not sure about the totals for african
and asian countries, since some parts of the population speak local
dialects as their primary language (even though Portuguese is the
official language), but the world total is certainly over 200 million.
Wikipedia puts the number at 208 million, which seems credible:

http://en.wikipedia.org/wiki/Portuguese_language
http://en.wikipedia.org/wiki/Portuguese_language#Geographic_distribution