monotone
adjective
°(of speech or a sound) having a single unvaried pitch.
°(of mathematics) property of a function to be either decreasing or increasing.
"The function is monotone while is not."
noun
°A single unvaried tone of speech or a sound.
"When Tima felt like her parents were treating her like a servant, she would speak in monotone and act as though she were a robot."
verb
°To speak in a monotone.