Not all of them do. Autism is much to broad a diagnosis for this kink of generalization.
She had a monotone voice.
I wouldn't have fallen asleep if the speaker had used something more than a monotone. The monotone humming of the engine soon lulled me to sleep.
My professor always has a monotone voice every morning.Since my grandfather is so old,he always speaks in a very monotone voice.
The Headmaster addressed the assembly in a monotone voice
Interaction with the textits also a monotone
Interaction with the textits also a monotone
Interaction with the textits also a monotone
Monotone or monotonous.
Interaction with the textits also a monotone
monotone
monotone
Interaction with the textits also a monotone