Mumble is an open source voice chat software for groups and gaming. It is designed for low latency, encrypts the connection between clients and the server, and runs on a server component called Murmur that you host yourself. It costs nothing to use.
Mumble is listed as open source and self-hosted rather than by company location, so the project is not necessarily European, and where conversations travel depends on where you put the server. Run that server in Europe and it becomes a European alternative to the American voice chat services, which suits gaming groups and communities that want full control at no cost.
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