for the 10 most spoken languages in the world
1 Mandarin Sino-Tibetan Chinese Characters
1051 China, Malaysia, Taiwan
2 English Indo-European Latin
510 USA, UK, Australia, Canada, New Zealand
3 Hindi Indo-European Devanagari
490 North and Central India
4 Spanish Indo-European Latin
425 The Americas, Spain
5 Arabic Afro-Asiatic Arabic
255 Middle East, Arabia, North Africa
6 Russian Indo-European Cyrillic
254 Russia, Central Asia
7 Portuguese Indo-European Latin
218 Brazil, Portugal, Southern Africa
8 Bengali Indo-European Bengali
215 Bangladesh, Eastern India
9 Malay, Indonesian Malayo-Polynesian Latin
175 Indonesia, Malaysia, Singapore
10 French
i was curious so i looked them up....the numbers like 1051 in Mandarin reprsents speakers by millions
http://www.krysstal.com/spoken.html
As for the Languages in Switzerland
German 74%
French 21%
Italian 4%
Rumantsch 1%
As for the closest Language to Amazigh, i do not have any idea about it!
As for the easiest langauge to learn according to me is English
PS: i do not claim knowing the answers of 2 first questions. but you said its ok to look for them so i googled them.