The kind of people that enjoy tinkering with new languages are not so common - and usually they enjoy writing their own language instead of looking at existing ones.
Unless you have a lot of users, with something really novel/special it is unlikely you'll get many people helping.
Your repository mentions "similar to C", but I see python-like indentation. Which makes me wonder what you're actually aiming for?
Once you have the core of the language the usual stumbling block is getting libraries available for HTTP fetching, database access, etc, etc. Do you have an idea of the kind of things that your language will be used for?
The more you document, and writeout there more likely it is you'll find people interested in what you're doing, but without that it'll almost certainly just be "your" project. (And there's no shame in that, or harm in it either.)
You need to have a roadmap or a list of issues that need user contribution.
Like, what enhancements do you need or what is left to be implemented in your language to make it fully functional/turing complete/free of memory leaks etc etc.