Pencil2d does not provide a save sound file option on the Export Files menu.
To overcome this ommission, you can deselect the visual layers and then export the sequence as a .MP4 file. Then load this into a sound edit package, say Audacity and edit the sounds and save the sound as a .MP3 file.
This can then be input into another project. You could also use the inport a layer option withon the File menu to load the sound from the initial project. This tends to involve more effort.
To copy a sound within a Pencil2D project can be done by selecting the sound and then using the copy, followed with Past option within the File manu.
If we operate in a logical manor, we’ll save these sounds in a Sound menu within the project directory. But sometimes we forget where these files are stored or they become corrupted.