ad. In a manner that is tedious, repetitious or lacking in variety.
ad. In a droning manner, that does not change pitch.
The Century Dictionary and Cyclopedia
In a monotonous manner; with monotony, tiresome uniformity, or lack of variation.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
ad. in a monotonous manner
Word Usage
"Each morning, when zoo dawn arrived, a starling gushed a medley of stolen songs, distant wrens cranked up a few arpeggios, and cuckoos called monotonously like clocks stuck on the hour."