noun
feigned voice; put-on voice; unnatural voice
A voice that is intentionally altered or not one's natural speaking voice, often for effect or deception.
電話で作り声を使うのはやめてください。
Please stop using a put-on voice on the phone.
彼は作り声で話しかけてきた。
He spoke to me in a feigned voice.
地声 refers to one's natural, unaltered voice, while 作り声 is a deliberately altered or unnatural voice.
Compound of 作り (tsukuri, 'making' or 'made') + 声 (koe, 'voice'), with rendaku voicing of 声 to ごえ.