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.
Monopolistically competitive markets have the following characteristics: 1  There are many producers and many consumers in the market, and no business has total control over the market price. 2  Consumers perceive that there are non-price differences among the competitors' products. 3  There are few barriers to entry and exit.