1. What is a retarded baby? Retarded babies refer to children with delayed intellectual development, usually with IQs lower than the normal range and significant developmental delays in language, cognition, social interaction, etc. Such children require special education and care to help them overcome obstacles and improve their quality of life. 2. What are the symptoms of a retarded baby? 1. Language barriers: including unclear articulation, slow speaking speed, poor language expression ability, etc. 2. Cognitive impairment: including poor memory, inattention, weak thinking ability, etc.