Adjective; typically referring to a person (self or others)generally under the influence or intoxicated as they attempt to form sounds and syllables to coalesce into words or sentences.
Origin: originating in 1997 in Port Jefferson station NY somewhere on Comsewogue school district grounds while engaging in copious amounts of marijuana consumption.
Person A: ghdjxotbosudbf
Person B: dude what the fuck did you just say?
Person C: that mothafucker is in mumble mode.
Person B: Here bro, just take another hit...
Person A: hdjdirbtbxizir <hits blunt again>