Is voice diction related to linguistics?
Yes, but it’s both more specialized and less exact at the same time. Linguistic studies are concerned with exact, detailed pronunciation and transcription: they use narrow transcription full of highly specialized IPA symbols. Voice diction uses broad transcription, which uses a simplified set of phoneme symbols, and aims for a reasonably authentic, understandable pronunciation. This pronunciation may then be modified to suit the demands of the music or the needs of the voice.