If really depends on what you want the language todo and gow much time you want to spend on it. A smart contract language (for Blockchains) - Rust A desktop

If really depends on what you want the language todo and gow much time you want to spend on it. A smart contract language (for Blockchains) - Rust A desktop executable with browser support - Nim A cross platform language (iOS, Android, Linix, Mac, Windows) - Dart Talk to GPUs - C++ or C on top of Tensorflow A toy language for learning compilers/interpreters - Python