I just had a fun training session!  I began in the backyard where there are less distractions, to get the dogs in the game. Then I took it on the road and practiced on our walk. I made a point of giving all cues in a whisper - we did sit, down, stay, touch, get it, bring, drop, heel, go sniff, leave it. My dogs responded just as they do when I use my regular voice!

If you always train your dog using the same tone of voice, you may find in an emergency, where you tend to use a louder voice, your dog may not respond as you  expect. Practice giving your cues in different voices such as a whisper as well as slightly louder than normal.

When  training your dog to respond to a whisper, make sure your dog is paying attention to you first. Use a kissy sound, hand clap or simply wait for eye contact,then give your cue in the new tone of voice.

Make sure your dog responds reliably to your cues in your regular voice before introducing the whisper or louder tone. Especially with the whisper, ensure your dog is looking at you before you begin.