[abhikandoi2000]

it is worth learning a new language to get a broader perspective on how to write software. you can easily write network services (that can scale later) in java, but not in javascript. you can easily create interactive demos using javascript (with html and css), but not with java.

as for how to stay focused, participate in a hackathon and build something using a new language. i find this helpful as it forces me to learn different features of a language. i don't like to learn a language by following tutorials which treat me like a baby learning to take its first step.

i have little idea about haskell, elixir, kotlin and scala, but here is some advice on the others: javascript: for web dev, interactive demos or quickly writing backend services python: writing scripts, backend for web dev, analyzing data swift: ios apps