As verbs the difference between grunting and muttering
is that grunting is present participle of grunt while muttering is present participle of lang=en.
As nouns the difference between grunting and muttering
is that grunting is a sound that grunts while muttering is something which is muttered.
muttering
English
Verb
(head)
Noun
(
en noun)
Something which is muttered
- I managed to catch a few of his mutterings .
A rumour.
Synonyms
* (something muttered) mumblage