Johnson said the word he used is like the "n-word," which at one time was acceptable to use but now is not.
"Now, we don't say the n-word. We refer to that word as the n-word," he said.
He said proper terms are "the little people," or people with dwarfism, and said people who wanted to find out more about this condition can look at a website run by a group called the Little People of America, www.lpaonline.org.
"So I wanted to say to all of those who may have been offended by the use of the term, the m-word, I want you to know that it was out of ignorance and not spite or hatred that I used that term, and please know that I will never use that term again," he said.
"I have been awakened to the sensitivities involved. So anyone who I offended has my deepest apology."