This chapter presents neurocognitive and neurolinguistic aspects of impaired first language acquisition, which leads to speech and language disorders. These include developmental articulation disorders and developmental fluency disorders, such as stuttering and cluttering. Dyslexia and language development disorders (DLDs) are also presented. Psycholinguistic and brain-physiological findings on these language development disorders are explained and related to unimpaired prenatal and early childhood brain development. Against the background of the child’s neuroplasticity and sensorimotor experience, clinical findings are discussed which also raise the question of a critical time window for first language acquisition.