That’s strange.  I’ve never heard of any Alexa device doing that, much less a Sonos.  Is it possible that an Alexa routine (or some other smart home control software)  has been setup to announce the volume?  I would look there.  Alternative, it could be a new setting for  Alexa devices, so you could look at the device settings in Alexa for your Beam.  I don’t have such a setting for me, but Amazon has been known to roll out changes like this to people in stages.

I’ve not experienced this. When you setup the Beam I assume you paired your TV remote with the Beam through the Sonos App. Perhaps the pairing has been lost for some reason. In this scenario the TV remote will be controlling the TV and not the Beam. If the TV is instructing the Beam to change volume via the HDMI ARC then it’s feasible that the default behaviour is for the Beam to announce the change in volume using the Alexa voice if there is no paired remote. This link might offer some insight:

https://support.sonos.com/s/article/3402?language=en_US

There is an interesting note: Only one remote can be programmed to control the Sonos home theater speaker at a time.

Have you changed remotes recently for any reason?

However, we use two remotes: the TV remote and the remote from a set-top-box, to control the volume of the Beam. I honestly can’t remember how I set both of these up as it was a while ago now and only needed to be done the once.

All I can suggest is you run through the remote control setup again.

Hope this helps.

Can you clarify how you are changing the volume?  By remote control or by voice?  Also, what type of TV are you using?  Is it perhaps a TV with FireTV built in?  

I had a similar issue, Samsung TV and Sonos Beam. Nothing to do with Sonos or Alexa, as it turned out. Somehow one of the family changed the TV settings and switched on voice guide under System->Accessibility. Set voice guide to off, and the voice previously heard when changing the volume disappeared.