The thing keeping me from agreeing with this is a qualifier. If it were "write like you talk when writing a X", where X could be substituted by tutorial, essay,

The thing keeping me from agreeing with this is a qualifier. If it were "write like you talk when writing a X", where X could be substituted by tutorial, essay, lesson, etc. I think I'd be more inclined not to disagree here. But as it stands "write like you talk" cannot hold true across the board for the set of all writing goals that exists. For example just watch any Tarantino film (or read the scripts), none of those characters talk like Tarantino does, I really would not want to watch a film where Uma Thurman walks around talking like him either. Entire fields of writing would not exists if this statement were true: Poetry, Rap, Music, Marketing slogans ("Think Different"), many types of Comedy, etc. EDIT: After a reread it looks he does suggest a qualifier, which is basically the general use case, which appears to be when "you want people to read and understand what you write" ie. informative essays, tutorials, emails that would occur in normal or every day communication situations, in which case I would agree.