You can make the phrase more conversational, such as “Alexa, would you please lower the volume for me?” But simply saying, “Alexa, louder,” or “Alexa, decrease,” will work too.
For example, say, “Alexa, set the volume to 6,” or simply say “Alexa, volume 6. " Alexa also understands volume via percentage. 0% would be mute, 10% would correspond to volume 1, 20% would correspond to volume 2 - all the way up to 100% which is volume 10. However, these percentages only come in increments of 10%, and only adjust if you mention your units of measurement (%) after the number.
You can also unmute by telling Alexa to set the volume to a desired level, as in, “Alexa, volume 3. "
