Most Using Language In World

What are the world's most widely spoken languages?

This question is a very interesting one that has a rather complicated answer.  Estimates of
how many people speak a language are quite general and can vary considerably.  For example, English estimates vary from 275 to 450 million, Spanish from 150 to over 300 million, Hindi from 150 to 350 million, and Russian 
from 150 to 180 million.

To further complicate matters, the definition of “speaker” can be vague.  Some surveys of languages give information on native speakers only.  Others count both native speakers and secondary speakers (those who use the language regularly or primarily even though it is not their native language).

Lastly, it is important to consider not only the population (number) of language speakers, but also the geographic distribution of these languages.  Some languages have relatively large populations of native speakers but are used almost exclusively in a few countries.  On the other hand, other languages have relatively small populations of native speakers but are used in many different countries as an official or national language.

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

Top 10 Languages:

Chinese* (937,132,000)

Spanish (332,000,000)

English (322,000,000)

Bengali (189,000,000)

Hindi/Urdu (182,000,000)

Arabic* (174,950,000)

Portuguese (170,000,000)

Russian (170,000,000)

Japanese (125,000,000)

German (98,000,000)

NOTE
Chinese Mandarin is the most widely spoken language with roughly 840 million speakers. The second most used language is Spanish with about 330 million, and English is the third most spoken language in the World with just over 320 million speakers.