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.
In a perfectly competitive market price is equal to marginal revenue. Price will also equal average cost. If price was greater than average cost the firms in the market would be making profit. This would lead to more firms entering (remember no barriers to entry) until profits are eliminated.