A dialect coach is a technical advisor who supports actors as they craft voice and speech patterns for characters in the context of productions be it in an on-camera setting (film, television and commercial), stage setting ("straight plays" as well as stand-up comedy, musicals and operas), or voiceover setting (radio plays, animation, audiobooks, video games, etc.).
Scope of work can differ widely from production to production and from actor to actor within a production. The coach's tasks may include researching real-world voices with an ear to regional, social or idiosyncratic patterns, curating primary source recordings for the actor's exploration, providing guidance and feedback during the actor's vocal design process (sometimes with input from directors or writers), running lines and monitoring vocal performance whether on set or in post (film/TV/commercials), during recording sessions (voiceovers), or at runs and previews (stage). A dialect coach will typically give notes on clarity, consistency, and credibility. Sometimes dialect elements are in place primarily to add texture to character or to the world, but occasionally authenticity is also flagged as a concern by a production. In such cases, the dialect coach will be tasked with monitoring the vocal transformation as it might be experienced by a native speaker in the audience. Above all, the coach strives to remove stumbling blocks to performance so that the actor's vocal transformation work does not distract the actor or the audience.
For on-camera productions, dialect coaches with a strong background in languages, cultures and dramatic writing may be involved in trans-creation or polishing of dialogue or other forms of written language (for signage, etc.), often with the support of native-speaker language consultants and culture advisors, including on-set language and culture monitors. Dialect coaches who have a background in linguistics may also be hired to design constructed languages ("conlangs").
Although the purview of the dialect coach is very different from that of the director, dialect coaches and directors often develop highly collaborative working relationships. Coaches may also be consulted by members of other departments including, for on-camera productions, writing, post, graphics, props, camera scenic and even wardrobe (for instance, when language elements appear on costumes).
Outside the acting world, dialect coaches are also employed to train broadcast journalists in speech (newscasters/newsreaders, etc.), to coach non-actor public speakers in presence and delivery, and to support singers, for instance, with diction challenges and in balancing tone and articulation in an unfamiliar language.