Hi William,
Thank you for reaching out, and welcome to Crowdin!
For your open-source project, it’s typically best to have a single project for all languages to keep things centralized and easier to manage. This way, volunteers can collaborate and see the overall progress in one place.
Crowdin does provide tools to review translations before they go live. You can set up a proofreading step in your workflow where either you or trusted volunteers can review and approve translations to ensure quality. This process can be as manual or automated as you prefer, and you can assign different roles to your volunteers to help manage the workflow efficiently.
To make your volunteers feel organized and appreciated, clear communication and recognition of their contributions are key. Regular updates on the project’s progress and shout-outs for exceptional work can go a long way.
I hope this helps 