That isn't a correction. Both "sped things" and "speeds things" are both legal English and both mean similar things (although as another commenter correctly notes, the tenses are subtly different).
In this context 'legal' can only mean 'having to do with the law' as there is no statutory definition of the English language (well not British English at least).
Downvoters can read this: https://english.stackexchange.com/questions/114620/speeded-v...
Sped is a perfectly valid English word. If you don't believe so then you should question your own knowledge of the language.