Adverbs are great. For a start, they can modify Verbs (She runs daily), Adjectives (The show is almost ready), and even other Adverbs (We read almost daily).
Secondly, they can tell us When something happens (I arrived yesterday), Where it happens (I stopped here for lunch), the Manner in which it happens (I ate quickly), the Degree to which it happens (I nearly choked), and the Frequency with which it happens (I always do that). These are the generally agreed upon Five Types of Adverbs.
But in English and Latin alike, you cannot expect an Adverb for everything! For example, there are Adverbs that means quietly (quiete and tranquille for example), but no Adverb that specifically means with a lowered voice. For this, we need the Ablative of Manner.
As the name suggests, the Ablative of Manner replaces only Adverbs that express Manner. And the Words are in the Ablative Case. These Words are commonly a Noun and an Adjective. For example, submissa voce with a quiet voice, magna voce with a loud voice, vultu laetissimo with a very happy expression, summo gaudio with the greatest joy.
Occasionally the Preposition cum with will be placed between the Noun and the Adjective, although it is not required. You may be familiar with the expression summa cum laude with the greatest praise.
‘Excellent!’ Marcellus shouts. ‘Where is this sack?’ Alan coughs and, in a lowered voice, responds, ‘I have already thrown the sack in the dumpster.’