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 spectrum of business enterprise ranges from perfectly competitive firms to monopoly. Between these two extremes lies the business landscape in which the vast majority of firms actually operate. Imperfect competition is a market structure with more than one firm in an industry in which at least one firm is a price setter. An imperfectly competitive firm has some monopoly power. This power depends on product differentiation that leads to a downward sloping demand curve, or it may result from the interaction of rival firms in an industry with only a few firms.