The adverbial case turns a noun into an adverb. That is to say, it makes the noun root which it’s attached to describe the manner of the verb of the clause in which it is found. It describes the way a verb is done. It usually can be translated into English as the suffix -ly or the word like when it is drawing a comparison. Just like pure adverb roots, they typically come after the verb.
You [speak] like him/her.
(Lit: You‘[speak] himly/herly.)
The cat tried [to jump] onto the shelf.
(Lit: Cat‘shelfontoed attemptedly.)
The dog [[ran]] away from me quickly.
(Lit: Dog‘meawayed speedily)
Verbal Derivation Implication
Verbed adverbials are a bit of a unique case as compared to other verbed cases. They create a predicative construction which describes an existential quality of the subject. They function very much like predicative adjectives in English or German (ie: The house is red (the noun is adjective)), except they’re predicative adverbs instead (ie: The house exists redly (the noun verbs adverbially)). Predicative adverbs cause the verbal derivational affix (the maroon/brown slots) to be dropped in the present tense, as the verbal element is understood contextually to be of an existential/stative nature.
The cat [is blue].
(Imp: Cat [exists] bluely)
It [is good].
(Imp: It [exists] goodly)
The dog [is fast].
(Imp: Dog [exists] speedily)
The bird [is flighted] / The bird [is flying] / The bird [flies].
(Imp: Bird [exists] flightedly)
The bird [will be] flighted again (implying that it isn’t flighted now, but once was).
*: Despite the fact that a future tense action verb derivation has been applied (-ušur), the stative element is still implied by -jat, and its tense is implied by -ušur. Because of the fact that -ušur is implying a future tense for the implied stative element, the regular future tense stative verb derivation -amar is not required.