In many posts throughout the years, I have actively mentioned learning a new programming language every year:
The push to focus on a single new language to better one's career originates from Andy Hunt and Dave Thomas in their amazing tome: The Pragmatic Programmer. Having gone through this excersice for the past 9 years, means there aren't a lot of mainstream languages left to explore. Due to this, I reached out to the greater Twitter community to help deciding on what 2021 might look like.
Idris, while a language that speaks to my love of types, is still extremely young. And wthout a clear sense of metaprogramming in the standard library, I might hold off on it until 2022 or 2023 even. Saying that, a language's age or adoption rate shouldn't deter folks from choosing it for a yearly project. A great example being: two years ago when I learned ReasonML.
Deno, while not a truly 'new' language, does have a sense to it that makes it something different than NodeJS. The adoption of Deno in serverless and CLI tooling does have a huge overlap with the team I work with day-to-day. This means that anything learned now, could be relevant to life at Glossier and beyond. Which funny enough, would be the first time work overlapped with a yearly language exploration... Ever.
2021 is going to be a year that the whole serverless revolution sees high demand and adoption (IMHO). There's a lot of space here to build 'mashup style' applications that have a thin vaneer of business logic and a large swath of infrastructure. Languages that can both build and run on these platforms will be relevant for anyone to explore in the coming year.
Also learning a language in 2021? Reach out on Twitter and share!