Neutral:
* Someone who mispronounces words: This is the most straightforward way to describe it.
* Someone with a pronunciation error: This is a more clinical way to describe it.
* Someone who has difficulty with pronunciation: This emphasizes the challenge rather than the mistake.
More informal:
* Someone who speaks with an accent: This is often used for people whose pronunciation differs from the standard, though it doesn't necessarily mean they're mispronouncing words.
* Someone who mangles words: This is a slightly derogatory term, implying that the mispronunciation is significant and possibly humorous.
* Someone who speaks incorrectly: This is a broad term that can encompass various errors, including mispronunciation.
Other options:
* A person with dyslexia: While dyslexia is primarily associated with reading difficulties, some people with dyslexia also struggle with pronunciation.
* Someone who is learning a new language: This is a common reason for mispronunciation, as learners are still acquiring the sounds and rules of the language.
Ultimately, the best term to use depends on the context and your intention. Avoid using language that is derogatory or offensive, and be respectful of the individual's situation.