Greetings KenzieandDougal,
Thanks for visiting the Apple Support Communities! I understand the speaker volume is quieter than expected with your Apple Watch.
Let's have restart your Apple Watch, and ensure your devices are updated:
Check to see if there is any debris that may be blocking the speaker that you can gently clear away: How to clean your Apple Watch - Apple Support
Additionally, check to see if there's water blocking the speaker: About Apple Watch water resistance - Apple Support
"To manually clear water from Apple Watch, swipe up on the bottom of the watch face to open Control Center, tap Water Lock, then turn the Digital Crown to unlock the screen and clear water from the speaker."
If the issue persists, unpair your Apple Watch from your iPhone, pair them back together, and then test the behavior: Unpair and erase your Apple Watch - Apple Support
I suggest having your Apple Watch inspected if further assistance is needed with the speaker: Get your Apple Watch ready for service - Apple Support
Kind regards.