The most spoken first 12 languages in the world data for 2018 estimated number of peoples ;

• Chinese > 1.3 billion
• English > 427 million
• Spanish > 266 million
• Hindi > 260 million
• Turkish > 220 million
• Arabic > 181 million
• Portuguese > 165 million
• Bengali > 162 million
• Russian > 158 million
• Japanese > 124 million
• German > 121 million
• French > 116 million

Pick one and start learning. Just learn anyone every two years and 20 years on average take control of the world.