Wikipedia's 'List of languages by number of native speakers' -
suggests that these 15 languages have most native speakers (and I've included where these languages are spoken) ...
Mandarin - China, Taiwan, Malaysia, Singapore
Spanish - Hispanic America, Spain, United States, Equatorial Guinea
English - Australia, Canada, India, Ireland, New Zealand, United Kingdom, United States, South Africa, Singapore
Hindi - India, Fiji, Nepal … (Mutually intelligible with Urdu)
Arabic - North Africa, Western Asia (Middle East), East Africa
Portuguese - Angola, Brazil, Mozambique, Portugal, São Tomé and Príncipe
Bengali - Bangladesh, West Bengal (India), Tripura (India), Assam (India)
Russian - Russia, former Republics of the Soviet Union, Mongolia
Japanese - Japan
Punjabi - Punjab region (India, Pakistan)
German - Austria, Belgium (Eupen-Malmedy), Germany, Luxembourg, Liechtenstein, Switzerland, South Tirol (in Italy)
Javanese - Java (Indonesia)
Wu - Zhejiang, Shanghai, southern Jiangsu (eastern China)
Malay/Indonesian - Indonesia, Malaysia, Brunei, Singapore
WUaS has recently finished beginning wiki pages for each of these 15, each of which WUaS is planning to create an accredited (in their countries), online, MIT OCW-centric, wiki university, - and all of which you'll find on the WUaS Languages' page -
And, again, WUaS plans for bachelor, Ph.D., law and M.D. degrees to be in the main and official languages in the above countries, and here's the main -
Nation States at WUaS page -
and check out the main nation states on this page, vis-a-vis the above countries.
And here are MIT OCW Translated courses, as a beginning of some of the courseware, and a model for translation -
(More countries (now 242+) and languages (7,105+) at WUaS to come, as beginnings of online, MIT OCW universities and schools).
EACH OF THE ABOVE LANGUAGES WILL BECOME A MIT OCW-centric UNIVERSITY IN THAT LANGUAGE ...
as you'll see in the "Ideas" section in one of the United Nations' languages at WUaS, e.g., -
Mandarin language (Chinese)
the above languages will dovetail with the U.N. languages, for example -
"This Mandarin language (Chinese) language, wiki, subject page at WUaS - http://worlduniversity.wikia.com/wiki/Mandarin_language_(Chinese) - will be an online university in Mandarin, paralleling the other United Nations' languages', wiki, subject pages, which will become MIT OCW-centric, WUaS universities and schools, also in those languages:
(Persian language: http://worlduniversity.wikia.com/wiki/Persian_language)
Again, what's far-reaching about WUaS, is that ... Each language will become an online, wiki, MIT OCW-centric university in that language.
And again, please remember that WUaS is wiki (editable web pages), so if you find friends who would like to wiki-develop an university in their country or language, please invite them to do so, or just email them a wiki page. This is a remarkable opportunity to develop a university in one's own country / language.