Heroes and heroines who rarely speak, cannot speak, or don't need to speak at all. Making a main character mute is often less about conveying diversity than about giving the audience a blank slate to project onto and as such it is most common in either video-games or art-house films.

This does not apply to characters who speak a made-up language.

This does not apply to animals or non-human characters if they make the range of sounds one would expect for their species (for example a dog barking or a cat meowing is how they "speak") - it is mostly used for humans, who are expected to be able to speak or for characters in settings where animals are able to vocalize beyond just the usual vocalizations found in nature (such as the talking animals of Jungle King or Lion King)

Some of these characters can end up being Pure Good if they meet all the criteria and have clear moral agency. However, since many of these characters lack a personality and clear motives they can only qualify if they depict their personality and motives clearly through their acts. Gromit is a good example of a mute heroes that qualifies as Pure Good.