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.
Pure competition is a market condition where the companies providing products offer the same features and price, making the difference between manufacturers minor, if not completely irrelevant. Once the products are part of pure competition, the sellers of those products often have similar sales.