* Language can mean different things: Do you mean spoken languages, programming languages, written languages, or something else?
* Popularity metrics vary: Different organizations and research groups use various methods to measure popularity. Some consider native speaker numbers, while others look at total speakers (including second language learners), internet usage, or economic impact.
To give you a helpful answer, please clarify what you mean by "language" and how you'd like to define "popularity."
For example, you could ask:
* "What is the fifth most spoken language in the world by native speakers?"
* "What is the fifth most popular programming language?"
* "What is the fifth most used language on the internet?"
Once you specify your question, I can provide you with a more accurate and helpful response.