Talked indistinctly in a low voice (8)
I believe the answer is:
muttered
'talked indistinctly in a low voice' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for muttered that I've seen before include "Spoke in low unclear voice, uttered subdued grumble" , "Murmured, mumbled" , "Spoke in low unclear tone" , "Talked in a barely audible voice" , "Spoke indistinctly in a low voice" .)