What do you call a person who does not know how to spell?

There isn't a single, commonly used word for someone who doesn't know how to spell. Here are some options, depending on the context and tone:

Neutral:

* Someone with poor spelling

* Someone who struggles with spelling

* Someone who has difficulty spelling

* Someone who is not a good speller

Informal:

* A bad speller

* A spelling bee nightmare

Formal:

* Someone with dyslexia (If the person has a learning disability that impacts spelling)

Humorous:

* A word butcher

* A spelling enthusiast (sarcastically)

It's important to be respectful when discussing someone's spelling ability. Remember that everyone learns at their own pace, and some people may have specific challenges.