I'm going to argue for a "no" on this one for the following reasons:
There is an ungodly amount of programming languages out there; creating a tag for each and every one would take quite a long time
I don't see why it needs to be specified. Most projects aren't locked to one programming language. If the project is to create a website with a backend; whether that backend is written in RoR/Spring/Flask/Phoenix/etc. doesn't really matter, and should be discussed between the participating members.
If the project is language-dependant, it should (and in my experience) does say so in the title of the project
Originally form @dannycolin in https://github.com/open-source-ideas/open-source-ideas/issues/76
Proposed change
Add programming language tags to issues and also show them on the website
Motivation
This would help people to filter project ideas by programming languages.
Proposed implementation
language : JavaScript
Suggestions, ideas are welcomed.