accentless
/ˌæksɛntˈlɛs/Definitions
1. adjective
lacking an accent or a distinctive way of speaking
“The accentless voice on the radio was surprisingly soothing.”
2. adjective
having no distinctive or noticeable quality
“The accentless style of the painting made it difficult to analyze.”
3. adjective
not having or showing any emphasis or stress
“The accentless tone of the speaker’s voice was almost monotonous.”