I want set 2 flarums with the same user system

I want to set 2 flarums with different languages, is there a solution which can let the 2 flarums use the same user system?

For what you are trying to do you might be better off using an extension like this one: https://discuss.flarum.org/d/23702-friendsofflarum-discussion-language

Algo thanks buddy, but this solution is not good enough, the tag names and desrcription is still the original language

You could probably use a SSO implementation that relies on one central system, like auth0 or similar solutions.

meihuak it depends on the sso service you'll use. It might need a custom extension, though most will be fairly simple to create. You could combine it with https://flarum.org/extension/v17development/flarum-third-party-login-only to force log in with that sso provider only (and unify your users in one system).

Remember that such an implementation will create separate users in each community still, though their information will be shared in the sso system.

I don't think truly re-using one database table users for multiple instances work as migrations might not work between them.