Fair play to Huawei for including a speaker on its self-titled Android Wear watch long before the software actually supported it. That being said, I'm sure Huawei Watch owners are wondering when their expensive gadget will have all of its parts activated so they can stop carrying around an extra quarter-ounce of extraneous electronics. According to multiple sources, that speaker will be activated soon, specifically whenever Google gets around to issuing the next version of Android Wear's firmware.
A user on Reddit says that he or she is currently using a test build of Android Wear on the Huawei Watch, and that the speaker is active with the new software installed. Calls can be made or answered directly from the watch, the user can set alerts for calls or texts, and the watch can use speech-to-text to read out menus for ease of access. Presumably third-party apps will have access to the speaker for whatever developers see fit to use it for.
Android Police can confirm through a secondary trusted source that this test build (still labeled Android Wear 1.4 (126.96.36.1996323) for some reason) enables speaker function on the Huawei Watch, and also that it comes with a new version of Google Play Services. It's possible that speaker software won't be ready for primetime in the next release, but it seems ready to go. There's no estimated time of arrival for the next firmware.