The option to mute the emojis in Predictable has been added as a feature request for Predictable 6.1! In the meantime, here is a tip to make them silent:
In Predictable, from the keyboard settings, select Manage Emojis. Select the emoji you want to mute and press the edit button in the top-right corner of the screen. Make sure it has no sound attached and relace the Speak text by a space. Save it and you are done!
