Of 526 civil parishes of Latvia 218 were not represented in "Latvju Dainas" with a single text.
Later these were dubbed the mute parishes.
But the cause of it was not the lack of singing tradition, rather lack of active collectors.

This is the map of collections published in Krisjanis Barons' "Latvju Dainas". It indicates the locations and number of texts received from them. When there is no indication - it is a mute parish...

Click on the part of Latvia you are interested in to see in detail.