1. Malay-Indonesian - 159 Million Speakers
Malay-Indonesian is spoken in Indonesia, Malaysia, Brunei, & Singapore.
"Hello" in Indonesian is "Selamat pagi".
2. Russian - 277 Million Speakers
Considering the size of Russia it was probably obvious it would make an appearance on the list but the language is also spoken in Belarus, Kazakhstan, Kyrgyzstan and Tajikistan.
"Hello" in Russian is "Zdravstvuite".
3. Portuguese - 191 Million Speakers
In the 12th Century, Portugal won its independence from Spain and expanded all over the world with the help of its famous explorers like Vasco da Gama and Prince Henry the Navigator. Portugal, Brazil, Angola, Cape Verde, Mozambique, Sao Tome and Principe, Guinea-Bissau, Timor-Leste, and Macau all speak Portuguese.
"Hello" in Portuguese is "Ola".
4. Bengali - 211 Million Speakers
Bengali is spoken in Bangladesh and India (Indian states of West Bengal, Tripura and South Assam).
"Hello" in Bengali is "Ei Je" (EYE-jay).
5. Arabic - 246 Million Speakers
Being the language of Quran, it is not just popular, but also one of the oldest languages of the world. It is spoken throughout the Middle East and found in other countries such as Saudi Arabia, Kuwait, Iraq, Syria, Jordan, Lebanon, and Egypt.
"Hello" in Arabic is "Al salaam a'alaykum".
6. Hindustani or Hindi : +445 Million
Hindustani is the first language of India and due to the population growing at such an incredible rate it is predicted to pass English and take second place within the next few years. It is also spoken in Nepal and Fiji.
"Hello" in Hindustani is "Namaste".
7. Spanish : +415 Million Speakers
Spanish is a national language in 20 sovereign states and one dependent entity, totaling around 442 million people. Apart from Brazil, Spanish is pretty much spoken in every country in South America. The language is also very similar to Portuguese with many Spanish and Portuguese speakers being able to understand each other.
"Hello" in Spanish is "Hola".
8. English : +500 Million Speakers
Even though English isn't the most spoken language of the world, it is spoken in majority of the countries of the world. In 2014, there were 58 sovereign states and 21 non-sovereign entities where English was an official language. It is spoken in countries such as United States, Canada, United Kingdom, Ireland, Australia, New Zealand, South Africa, Singapore, Malaysia, India, Hong Kong, and Commonwealth of Nations.
9. Mandarin : +850 Million Speakers
Mandarin is the most popular language in the world as it is spoken in the most populated country in the world.
Even though mandarin is spoken by nearly double the number of people speaking English, it is one of the most toughest languages to learn.
"Hello" in Mandarin is "Ni hao"