10 Words That Started Out As Errors

Language change is driven by mistakes. If every generation of children perfectly learned what they heard spoken around them, then languages would be exact duplicates of themselves, never changing over the centuries. Clearly, this isn't what happens. Words have very often been formed by mishearings, inversion of sounds, dropping and adding of sounds, and other all-too-human errors.
Here are 10 words that started out as errors.