I think of it this way, find a language that you like (hard to choose I know). Get to know it on an expert level (there is a talk about ~5 years you can become an expert at anything...), and know the supplemental languages that go along with that language.
For example: If you are a Java or C# web developer, you should be an expert in the core language and also be moderately efficient at the supporting frameworks and languages (Javascript, HTML, SQL, NoSQL, Scripting, Angular, etc).
After you gain an expert knowledge base in a language, then the sky is the limit on what you concentrate after that. Once in the workforce, my primary language (.NET/C#) became almost boring so I've picked up a side framework for fun (NodeJS because Javascript is the language and I already have a modest knowledge in it). But I also have a beginners/intermediate knowledge in C/C++, Java, Python, and PHP.
The real key is this, if you engineer in a small set of languages day in and day out as a job, you will eventually become an expert in it. So choose something you like and can obviously find a job in. Then everything else is fun-time or mental growth.