unintelligible

adjectives

poorly articulated or enunciated, or drowned by noise
"unintelligible speech"
is derived from
antonym
is similar to
spoken as if with a thick tongue
"the thick speech of a drunkard"; "his words were slurred"
see also
difficult to understand
"the most incomprehensible thing about the universe is that it is comprehensible"- A. Einstein
not clearly understood or expressed
is derived from