YOU SHOULD LEARN
Typescript— Most used, versatile, easy, large developer community and WORA (Write Once Run Anywhere), scripting, frontend, backend, ML(be aware of its dependency hell).
Python — easiest to learn, wide application (backend, ML, data science, visualization, scripting, hacking), adoption continues to grow.
Kotlin/Swift — versatile, simplification of existing native app development.
C# — Platform agnostic, simple, general-purpose language, can be used to develop any type of application, game development, VR, AR.
Go — solves scalability issues, simple elegant code, easy to learn, the language of the cloud, DevOps, backend, servers.
YOU SHOULD CONSIDER
Java — big data, in high demand worldwide, enterprise king, the core language of industry-standard tools like Apache Kafka, spark, hive, etc.
R — statistics, ML, Data Visualisation, slow and data-intensive.
Dart — One codebase for Android, iOS, Web App, Desktop/Laptop Programs, Linux Programs, embedded. Flutter.
Rust — memory management, Linux kernel, highest pay.
YOU SHOULD NOT CONSIDER
Ruby — better tools are available now. (Sidenote: Github, Gitlab are written in Ruby on Rails framework, and still the first choice of many startups for easy MVP and fast deployment)
PHP — lacks good debugging tools (compared to other languages), relatively low pay, still extensively popular, tough competition from python. [Earlier versions of PHP paid less attention to security features, presently, it’s as robust as any other language]
C++ — bridge b/w LLP and HLP, memory unsafe, game engine development, OS level, embedded, fintech, trading.
Super-new and very niche-specific languages which do not have a healthy community.[For more on that, please refer to the end of the article]