Language Myths covers a range of misunderstandings about the nature of language, and not just English: there's cross-language comparison here too.
The articles are written by a range of 'stars' among linguists, including some names of theorists you might recognise, and using concepts both familiar, and those beyond our scope at A-Level.
Having said that, it's lucidly written for the general reader and a great way to expand your knowledge and revisit some concepts in use.