A project that starts with a person, the best way is to put as open project, and try to join a community.
You create a repository on Github for your language project - put in the code, and the documentation: the documentation must be quite complete, justifiable, even the language specification itself, without worrying about the code, and finally, the documentation of your code.
Of course Github is just the most used system - but anyway it’s important that it’s open source and in a public repository - the service can be bitbucket, an instance of gitlab, etc...
Now, the recently created languages that had a relatively fast reach have one thing in common: they were all created by multibillion-dollar mega-corporations - go, Kotlin, Swift - for example. It’s another type of release, when you have the ability to employ dozens of professionals full-time to create your language - including the marketing team to create advertising campaigns.
An important factor is whether your project is going to have any real innovation - filling a niche that doesn’t exist in the spectrum of languages, or whether the goal is just more didactic: for your learning and who gets involved in the project. There are very good languages in the first category fall by the wayside, even after some initial traction. Or have you heard of "Boo", a statically typed language with the Python-based syntax that runs on the . net VM? In the second category, the project will, at least in the initial months, be restricted to a small circle of users anyway.