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 Features of Competitive Markets. The third and final feature of competitive markets is that firms can freely enter and exit the market. In competitive markets, there are no barriers to entry, either natural or artificial, that would prevent a company from doing business in the market if it decided that it wanted to.