iHelp BR's Filipe Esposito has noticed that the latest iOS 11.2.5 beta includes icons for a variety of scene icons, some of which explicitly reference Siri being turned off on at least one speaker. In other words, you could prevent Siri from accidentally interrupting your study session. Esposito also believes that lines of code might reference support for multiple voices, although that's less than certain. It would make sense when the HomePod may have to be shared by an entire household, especially when Amazon and Google already offer the feature, but Apple hasn't supported multiple users on devices beyond the Mac.

Neither clue guarantees that a HomePod release is right around the corner. It likely depends on a finished release of iOS 11.2.5 or later, and that's not including the usual challenges with producing enough units to satisfy initial demand. However, these tidbits suggest the wait might be measured in weeks rather than months.