Specific language impairment (SLI) is diagnosed when a child's language does not develop normally and the difficulties cannot be accounted for by generally slow development, physical abnormality of the speech apparatus, autism spectrum disorder, acquired brain damage or hearing loss.
Perfect competition. A perfectly competitive market is a hypothetical market where competition is at its greatest possible level. Neo-classical economists argued that perfect competition would produce the best possible outcomes for consumers, and society.
The sellers in a purely competitive market are price takers. The market set the price and each seller react to that price by altering the variable input and output in the short run. In the long rung they can alter the scale of plant (size of the fixed input in each short run period).