Introduction: Dysphasia is a language disorder in which there is an impairment of speech and of comprehension of speech. Acquired childhood aphasia is rare but has important conceptual implications for developmental neuropsychology. Aim: Studying long term monitoring EEG in patients with acquired dysphasia, whether giving history of epilepsy or not, to stand on the different EEG pictures related to it, identify their causes and calculate their ratios. Subjects and Methods: 40 patients, males and females, with age ranging 3-16 years, giving history of acquired language disorder were studied for 1. Long-term, sleep and wake EEG, 2. Psychometric assessment; Childhood behavior checklist (CBCL), Childhood autistic assessment scale (CARS) and Vineland Adaptive Behaviour Scales (VABS), 3. Auditory evoked potential studies: early (BAEPs) and –whenever possible-late (P300). In addition, 20 normal age and sex matched subjects were examined for; 1. Auditory evoked potential studies, 2. CBCL and VABS. Results: The patient group (24 males and 16 females), were divided to group I giving history of epilepsy or having epileptiform EEG and group II negative for either. Group I showed heterogeneous EEG pictures, and heterogeneous diagnoses, yet 7 patients showed sleep induced potentiation for epileptiform changes. Group II patients chiefly had autism spectrum disorder. Statistical comparisons and correlations were performed for patient groups and controls. Conclusion: The boundaries between epileptiform EEG, epilepsy and epileptic encephalopathy are clear by definition, but they usually merge in clinical cases. The onset of epilepsy in brain systems involved in social communication and/or recognition of emotions- during the brain developmental period- can initiate speech and language development impairment. Also, it can occasionally be the cause of -or may aggravate preexisting behavioural disturbances.