Is Teamspeak necessary for OpenCommunity Raiding?

[Tamo 49]

Is it compulsory to join the TeamSpeak to participate in OpenCommunity Raids?

[Viridian 191]

Raids require a lot of coordination and fast communication between team members. We use TeamSpeak to coordinate and you will be required to at least join and listen, even if you do not talk yourself. However, at some encounters there are special tasks and generally there are roles which you cannot fulfil, if you are not able to talk.