Abstract
<jats:p>The work is organized into sections covering the most relevant developmental and functional language disorders, integrating theoretical foundations, clinical cases, and intervention guidelines. It combines scientific rigor with a pedagogical approach: each chapter includes precise definitions, comparative tables, clinical vignettes, reflective activities, and summary syntheses. It begins with an introduction to speech therapy as a scientific and healthcare discipline, focusing on its evolution in Spain and its international projection. It defines the concepts of language, speech, tongue, and voice, and presents the psychopathology of language as a field that integrates tékhné (technical knowledge) and epistḗmē (scientific knowledge). This framework highlights the specificity of the subject and its necessarily interdisciplinary character, in dialogue with neurology, cognitive psychology, and clinical linguistics. Next, it presents the dual perspective guiding the study of altered language: the clinical, focused on evaluation, diagnosis, and intervention; and the research perspective, aimed at explaining underlying cognitive and neurological mechanisms. The need to integrate both views to ensure evidence-based practice is emphasized. Among developmental disorders, it analyzes Developmental Language Disorder (DLD), including terminological evolution, clinical profiles, explanatory hypotheses, and differential markers in Spanish. Its assessment is described through standardized tests and qualitative discourse analysis, as well as early and intensive intervention strategies. It also addresses functional dyslalia, one of the most frequent childhood conditions, characterized by articulatory errors without organic basis. Diagnostic criteria, underlying phonological processes, and phases of speech therapy intervention from auditory discrimination to phoneme automation in discourse are detailed. Another section deals with reading and writing disorders, particularly developmental dyslexia, linked to phonological deficits and difficulties in the grapheme-phoneme route. Cognitive bases, importance of early detection, and phonological and reading intervention guidelines are presented. In the realm of acquired disorders, aphasias are reviewed, classified according to neuroanatomical and functional criteria, with their clinical manifestations and rehabilitation strategies. A chapter on amusia, understood as a little-addressed form of auditory agnosia that offers an innovative approach, is included. The text emphasizes clinical classification according to course (developmental or acquired), nature (functional or organic), and affected linguistic levels (phonological, morphosyntactic, semantic, pragmatic, and prosodic). This systematization allows for differential diagnosis and support for intervention. Overall, the manual is a reference teaching resource linking the Spanish academic tradition in language psychopathology with recent international consensuses. Its aim is to train speech therapists capable of integrating scientific knowledge, clinical sensitivity, and ethical commitment to intervene in healthcare, educational, and social contexts.</jats:p>