Of course, you can. However, the question misses the point. It’s not about how many programming languages you know. It’s about how much expertise you have in the areas that matter.
If you are good at Python, you’ve already proven that you have expertise in the technical programming area. Now, it’s much more about how good you are in other relevant areas that have nothing to do with programming—but are at least as important.
As a programmer, communication is king. You need to communicate with clients to understand what the clients want to accomplish and what is their pain point. Either you work as a freelancer, as an employee, or on your project. In any case, you have clients, bosses, or users who have pain points that you must resolve. This skill is far more important than knowing the second or third programming language.
It’s about this old debate: what is more important effectiveness or efficiency. Effectiveness is the ability to reach a goal no matter what. Efficiency is about using minimal resources. In practice, effectiveness is far more important because if you don’t have a goal in mind, what’s the point of using minimal resources? Similarly, what’s the point of knowing a lot of programming languages if you don’t solve real problems?
So to answer your question: it’s way enough to know one language. If you’ve mastered one language, focus on practical matters like your communication and marketing skills.

While working as a researcher in distributed systems, Dr. Christian Mayer found his love for teaching computer science students.
To help students reach higher levels of Python success, he founded the programming education website Finxter.com that has taught exponential skills to millions of coders worldwide. He’s the author of the best-selling programming books Python One-Liners (NoStarch 2020), The Art of Clean Code (NoStarch 2022), and The Book of Dash (NoStarch 2022). Chris also coauthored the Coffee Break Python series of self-published books. He’s a computer science enthusiast, freelancer, and owner of one of the top 10 largest Python blogs worldwide.
His passions are writing, reading, and coding. But his greatest passion is to serve aspiring coders through Finxter and help them to boost their skills. You can join his free email academy here.