We were delighted that Professor Martin Ball invited us to guest edit this special edition of Clinical Linguistics & Phonetics on ‘Covert Contrasts’ in child speech. Although the idea of covert contrasts is not new, there has been renewed interest in the topic recently due to new developments in the methodologies used to uncover these types of contrasts in child speech. These developments are highly significant, in our opinion, because they provide for the first time the potential to identify reliably the presence, and therefore also the prevalence, of covert contrasts in child speech.