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.
Perfect competition is the opposite of a monopoly, in which only a single firm supplies a particular good or service, and that firm can charge whatever price it wants because consumers have no alternatives and it is difficult for would-be competitors to enter the marketplace.