There are many languages you can use for Machine learning. However, Python and R have the best support for it. Python is more popular in software development teams as it can be used to write more robust, and maintainable code while r is used more in academic and research teams as it is very easy to write scripts in it. Both have a huge number of libraries for machine learning which is why they are so popular.
If you are looking for an online course to learn Machine Learning, I recommend this Machine Learning Certification by Intellipaat.