I think a callout the first couple of times is fine (still not my preference, but I think this is a cultural thing - the US style "how can I help you" in retail

I think a callout the first couple of times is fine (still not my preference, but I think this is a cultural thing - the US style "how can I help you" in retail rubs me up the wrong way too). But I think after that it'd be very much preferable to taper off - especially the sounds. As another commenter said, know your audience - your icon is obvious and descriptive, so we don't need to be told 20 times what it does.