Java: With a steady rise in the number of Android users, the popularity and usage of Java programming language went up sharply. It is a favorite server-side language for backend development. Java has long-term compatibility and popular with most developers. Websites like Java World, Developer works by IBM and Stack Overflow are based on Java.
Python: Python is a general purpose programming language that is used for apps, both desktop and mobile. Python is used in data mining applications too. Youtube, Yahoo Maps and Quora are built with Python. Python as a scripting language is well suited for data science and computational analysis. It is used in the development of Google, NASA, Reddit and PBS.
JS: JavaScript is a dynamic scripting language that is found on most web pages. JS is compatible with most web browsers and is a widely used scripting language. Also being proficient in the use of jQuery can help you add features easily without adding tons of code. Amazon, eBay and LinkedIn use JS.
C++: C++ continues to remain on the scene as a high-performance programming language for a range of applications, from desktop and web applications to games and system software. C++ is used in the development of Amazon and Microsoft Windows. Even software for fighter jet planes is written in C++.
PHP: PHP is a server-side programming language that is popularly used on most web sites. Complemented by SQL and JS, PHP skills are important for developers. PHP is used in Facebook, Wikipedia, and Tumblr. It works seamlessly with MySQL and RDBMS.PHP is used as a foundation for CMS (Content Management Systems) like WordPress.
Visual Basic: .NET is an object-oriented programming language.
Perl is a UNIX-based scripting language that is used for data mining and script automation. Perl programming has uses in graphics, network, finance and CGI.
R is a programming language that allows for complex numerical computations that can be useful for data analysis.