They're typos. Here's a carefully written article: http://www.educationbug.org/a/typos-vs-misspellings.html http://www.educationbug.org/a/typos-vs-misspelling

They're typos. Here's a carefully written article: http://www.educationbug.org/a/typos-vs-misspellings.html http://www.educationbug.org/a/typos-vs-misspellings.html