Smart to ask people about what they'd like to learn, not just what they know already. Sometimes second on the list is just as important. For example, English is not the favored language of anything like a majority of the world, but it is everybody's second favorite by a landslide. This survey revealed a strong pent-up demand for vue.js.
Also smart to ask about satisfaction, as it's definitely a more useful metric than market share in figuring out what to learn.