Go is one of the better languages for upskilling on the job. Realistically learning syntax of most languages doesn't take too long. If the new hire has a good

Go is one of the better languages for upskilling on the job. Realistically learning syntax of most languages doesn't take too long. If the new hire has a good grasp of all the Concepts/Techniques from comparable languages, that would not take too long either, and then you're left with learning environmental aspects only such as libraries and toolchain. I've personally picked up a new language in a job many times with learning time of a month or two to be pretty much as effective as the majority of the team. This only works for some people, but what worked for me is while starting reading the language reference and one good up to date book on getting started in the language, both cover to cover. Pairing is very effective here as well in picking up the nuances of how to use the toolchain efficiently, but youtubes can help if pairing isn't available. That said I wouldn't take Python only developers and try to get them to learn C++ or Haskell on the job!