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.
Distinguish between monopolies and competitive firms. In a perfectly competitive market, there are many producers and consumers, no barriers to exit and entry into the market, perfectly homogenous goods, perfect information, and well-defined property rights.