C, C++,Java, JavaScript, Go, R,Swift,PHP,MATLAB and Python

Python is widely accepted as the best programming language.

Java is popular choice in large organizations and it has remained so for decades. Java is widely used for building enterprise-scale web applications.

Go programming language is a programming language built by Google. Go provides excellent support for multithreading and so, it is being used by a lot of companies that rely heavily on distributed systems.

R programming language is one of the most commonly used programming languages for Data Analysis and Machine Learning.
Swift is the programming language that is used to develop iOS applications. iOS-based devices are becoming increasingly popular.

PHP is among the most popular backend programming language. Though PHP is facing tough competition from Python and JavaScript, the market still needs a large number of PHP developers.
MATLAB is a statistical analysis tool that is used in various industries for Data Analysis. MATLAB is used widely in the Computer Vision and Image processing industry as well.

Outlook

• Python and JavaScript are hot in the startup world. Many startups use Django (Python), Flask (Python), and NodeJS (JavaScript) as their backend frameworks. Python and JavaScript are easy-to-learn and therefore considered the best programming languages to learn for beginners. Moreover, both of them also provide a huge market opportunity. Therefore, those who are looking for a job change may also consider learning them.
• Java and PHP are hot in the corporate world. Many organizations use Spring (Java) and Codeigniter (PHP) as their web backend framework.
• R and MATLAB are hot in the Data Analytics world. If you wish to develop a career in Data Analytics or Data Science, these are the languages to learn.
• C/C++ and Golang are the top choices in building low-latency and scalable systems.

Resources for online learning:

https://www.coursera.org/

Learn Python on YouTube