Unlike most monographs on Spanish phonology and morphology that approach these topics from a structuralist or generativist framework, this volume is written from a less traditional point of view. More specifically, it emphasizes quantitative evidence from sources such as usage-based studies, psycholinguistic experiments, corpus data, and computer simulations. Arguments are presented to demonstrate that these kinds of evidence are crucial for establishing theories of language that relate to the psychological mechanisms involved in producing and comprehending speech, in contrast to theories about abstract linguistic structure. A range of topics is covered including morphological parsing, nominalization, stress, syllable structure, diphthongization, gender, morphophonemic alternations, and epenthesis. An appendix is included that serves as a primer on quantitative linguistic research. It discusses how some of the cited experiments were carried out, provides an introduction to statistical analysis, and discusses tools that are available for conducting quantitative research on the Spanish language.