Purpose: This article was written as an editorial to a collection of original articles on apraxia of speech (AOS) in which some of the more recent advancements in the understanding of this syndrome are discussed. It covers controversial issues concerning the theoretical foundations of AOS. Our approach was motivated by a change of perspective on motor speech that has taken place in neurobiology, neurolinguistics, phonology, and phonetics during the past few decades. Method: The literature on AOS is reviewed from 3 different but overlapping perspectives--that is, a disconnection, a motor memory, and a fine motor skill perspective. Separate sections are devoted to the delimitations of AOS from oral facial apraxia, dysarthria, and phonological impairment. Conclusions: We conclude that many of the still unresolved conceptual issues about AOS arise from an underspecification of existing models of spoken language production. We suggest that phonological and motor impairments of sound production should be studied by an integrated approach.