Top Ten Most Useful Languages to Learn
Rated by:1. Number of speakers: With how many people in the world can you communicate with this language, including languages that are similar.
2. Geographical distribution: Over how many lands is this language spread/in how many parts of the world can you use it.
3. Cultural and historical significance: can you use the language to understand scientific words/is the language important for a certain culture

Beside being today's most important language of international communication, it is also the language of the perhaps biggest former colonial empire with both a big number of native speakers and countries all across the globe.
Regions:
Native language: E.G. british Isles, North America, Caribbean, South Africa, Oceania, Singapore
Administrative language: E.G. Eastern Africa, South Asia
English is not only the most important language for international communication but also the language of the biggest former colonial empire. It's many words of Latin origin allow you to understand scientific words as well.
Regions:
Native: Britain, Ireland, North America, Caribbean, South Africa, Oceania, Singapore
Administrative: East Africa, South Asia (...)
Fields: politics, economy, computers, internet, music...
Countries: United Kingdom, Australia, New Zealand and the U.S. English is their native language, spoken every day and English is spoken as a 2nd or 3rd language in some other countries.
English is the most useful language of all.
English is the international language, if you can't speak english. You do not have access to a lot of stuff! I'm French and I can say it's so annoying to can't know speak English.

The biggest colonial empire after Britain, or maybe even just as big as Britain or bigger than Britain. Actual number of native speakers has surpassed that of English. With Spanish, you can also understand Italian and some other romance languages, as well as scientific and other international Latin words.
Regions: Spain, almost the whole of America, and even southern USA.
I am a native English speaker, so I'm going with Spanish because there are millions who speak it around the world. If I hear a foreign language, it's usually Spanish. Very rarely, I will hear people speaking German in the U.S. but that's it! We should all know some Spanish.
It will provide many job opportunities that will otherwise be unavailable.
Spanish is the most useful. I am learning it right now.

Number of speakers: not so big, but distribution is quite big through colonial empire. Culturally very important either to induce scientific Latin words or because of being the language of the dominant culture of Europe from 17th century until first half of the 20th century (together with Britain, most modern inventions setting of fashion trends together with Italy, cuisine etc.). The language of the nobility and diplomacy.
Regions: France, Belgium, almost whole of northern and western, also central Africa, Haiti, Guyana, Canada.
French language is the official language of 29 countries and 57 countries and regions where French is the first ("mother") or customary language, and a total of 84 Member states of the International Organisation of La Francophonie. Approximately 274 million people are speaking the language. According to a demographic projection, total French speakers will number approximately 500 million people in 2025 and between 650 and 700 million people by 2050, 80% of whom will be in Africa.
Official language in 29 countries, spoken in 57 countries; in 2050, French will be spoken by more than 1.1 billion people (from U.N.).
Today, It's the 4th linguistic space in the world behind English, Chinese, Hindi but before Spanish; Arabic, and Portuguese.
So yes, it's definitely one of the language we should learn, I already started, amazing is it.
It was the lingua franca so even if there are less French speakers than Spanish or English speakers, French is spoken on every continent and is very significant (just behind English).

Biggest number of speakers and its economy is on route to be the biggest in the world. I am currently learning Chinese and it isn't as hard as people say it is. A lot of experts say that Chinese is the language of the future and that demand for Chinese speakers is only going to get higher. It is a great language for business and it sounds great in the ears.
The biggest number of speakers in the world, big diaspora in Southeast Asia and many other countries.
An important language of East Asia through the script but a big disadvantage is that you can't understand any international or scientific words with it.
Chinese has the biggest number of NATIVE speakers, though to be technical, Chinese is broken into a minimum of six distinct dialects. Counting second and third-language speakers, English is the most-used worldwide.
You need to learn Chinese so that you can talk to many people.

The times when Russian used to be second most important language of the world because of the Soviet Union are over, but it is still among the top 6. Numbers of speakers is not among the biggest, though still quite big. Culturally not so important, but still very important through Russia's strong political role and the distribution across a vast territory.
Regions (native, administrative and culturally related): Russia, Belarus, Ukraine, Baltic States, Central Asia, Georgia, Armenia.
Yes its useful...

Esperanto is the international language. It is designed to be just that and truly deserves its purpose of becoming a world lingua franca. Why? Because:
1. Esperanto is an artificial language, free from national/ethnic origin, without the baggage of culture, politics, nationalism, and imperialism. The problem with having a language of national/ethnic origin as a lingua franca is that it creates a dominance sphere for only those who speak it natively. Others are left out and considered inferior, and they are forced to learn the dominant language while those who happen to be born as native speakers of the "dominant" language don't need to learn another language. (This is on a global perspective. I believe national standards should be followed. If you want to live in a nation where a language is spoken, you should respect that and speak their language to allow you to fully integrate into their society). It can also endanger other languages and their culture. Esperanto ...more
It's making a comeback!

It's a beautiful language with many dialects and muslims speaking it. Since so many different people are speaking it, it may give you opportunities you never even knew existed.
Considerable number of native speakers spread over a vast territory. Culturally and historically an important and/or respected language in Muslim countries, from western Africa to southeast Asia.
Regions:
Native: North Africa, West Asia
Culturally important in: West Africa, Sahel, Horn of Africa, Turkey, Persia, Central Asia, Pakistan, Indonesia.
For certain job fields, this is a highly valuable language to learn

Norwegian is not only a useful language but it's also easy and very fun to learn.

Even though Italian isn't that spoken in the world today, it is still the fourth most learned language in the world after English, French, and Spanish.
The language is rapidly increasing with around 4.8 million people adding on to the total number of speakers. The language is also used as a commercial language in former colonies like Libya, Eritrea, Somalia, and Ethiopia. Italian is also very common in Argentina with around 1.5 million speakers which is the same number of people as 4 Iceland. This is why Italian in my opinion is a very useful language.
Apart from being a relatively big language in Europe, it is probably, alongside with Greek, the most important cultural and historical language which, through its relatedness to Latin, opens the doors to understanding the meaning of most scientific and other international words. And even when leaving aside its closeness to Latin, Italian has been the most important cultural language in Europe in the Middle Ages and the early modern era until the 16th century in fields like Christian religion, music and cuisine.
Many people believe that Italian isn't useful to use as it's only spoken in Italy, but you're wrong. Over 65 million people speak this language with an additional 30 million using it as a second language.
Italian is used in San Marino, Vatican, Switzerland (Ticino and parts of Grisons), Istria, and has a lot of speakers in Ethiopia, Eritrea, Somalia, Libya, Canada, US, Argentina and Australia.
LEARN ITALIAN NOW!
The English is a lingua franca, two Italian words. English and French have a lot of Italian words. If you know Italian, you can understand: French, Spanish, and Romanian... Latin and Italian are similar: chemistry, biology and the majority of sciences used Latin words.
It's great to learn it. It makes it easier to learn other languages and a lot of people speak it in southern India, especially Tamil Nadu.
U should learn

Native or administrative language of a giant number of speakers. Can be used for communication in India, Pakistan, Nepal. The only reason why it isn't a UNO language as well, is probably that these countries have English as an administrative language, too.
Hindi is one of the most useful language in India. I know a few elitists are going to claim it is Urdu but Urdu is used nowhere instead of sher- o- shayari and qawwali. Al political discourse, scientific discourse and intellectual discussions happen in Hindi. Most people in India do not know what science is in Urdu, but we know it is vigyaan in Hindi.
I'm a Hindu monk so I speak Hindi. We study English too. Hindu monk teachings say multiple language learning helps expand the mind and calm the way of thinking.
This is very useful language. This is most spoken language of the world. Hindi speakers are present in every country of world.

Not only does this beautiful language have 128 million native speakers, but learning Japanese gives you access to its beautiful culture and one of the most influential pop cultures in the world. So if you want to enjoy your favourite anime, manga, and JRPGs in their native tongue, this is the language for you.
Another language of a big former colonial empire with speakers in many parts of the world, though not as many English or Spanish.
Regions: E.G. Portugal, Brazil, Angola, and Mozambique.
It is now part of the most useful language all over the world and most especially Nigeria as a whole.
Very useful if you want to literally to know the English lyrics of Gangnam Style. Like pyeongyoja prounounced (pong-yo-ja) At the first chorus stanza, you'll hear it 60 nanoseconds in the music video because he dances Gangnam Style in the building literally means in the Romanized Korean English translation, let's dance my friend!


Considering this is a dead language, Latin should be a bit lower. It is not really practical since most people in the world don't speak it unless you are in the Vatican, or you're deciding to be a teacher, excel in law, science, or if you want to straight up study the history of Rome. Otherwise, it is somewhat essential into knowing some parts of the romance language if you get a good grasp of it, but generally aiming for that goal is still not practical, but learning Italian first is a much more easier language as it will give you more of an understanding of Latin since it is one of the closest language as of that language; don't let this stop you though - if you are learning for the sake of fun, go for it.
Same with French, Italian and Romania.

It may not seem useful to you, but so many people don't have any other option. You'd have good job opportunities where you actually help people
Since ASL is the most spoken version of sign language, I would definitely recommend learning it! You would be able to talk to people that can't hear too well.
A considerable number of native speakers in Turkey and can be used for communication throughout Asia from western Asia to the uyghur region in China.
Regions: Turkey, Azerbaijan, Turkmenistan, Uzbekistan, Kazakhstan, Kyrgyzstan, Uyghuristan (China)

I think this is he most beautiful lauguge in the world because it is so rich and magical! I am from Amarica and for me its really difficult.
If you know polish you can understand russian, czech, ukraine, slovakia...
More than 200 million people speak Indonesian. It is very useful, because when we go travel to Indonesia, we will find better communication. Seriously, this country is so beautiful! It is the largest archipelago country with a lot of amazing places to visit! :)
Indonesia is going to be the greatest country in several years, so get ready and learn Indonesian language.