Final answer:
Language policy encompasses rules and guidelines about the use and status of languages, while language planning involves the development of official languages. Slang is informal language use not recognized as standard, and public policy can include governmental decisions influencing language use, such as designating an official language. Sociolinguistics studies the social aspects of language use.
Step-by-step explanation:
Language Policy, Planning, and Related Concepts
When discussing language policy, we refer to the regulations and guidelines determining the status and use of languages, as well as the rights of speakers. An example is India, where although the official language is Hindi, English and several local languages are widely used. Language planning, on the other hand, involves the selection and development of official languages in government and education. A case in point is the proliferation of English-based pidgin languages in places such as New Guinea, where unique grammar and sentence structures are created to facilitate communication between different linguistic groups.
Slang represents the informal words or phrases unique to a particular culture or subgroup and not officially recognized within a language's standard form. This could include slang terms used by musicians in their lyrics. Furthermore, in the context of the United States, while English is widely considered the de facto official language, over thirty states have enacted laws designating English as their official language to promote assimilation and reduce costs associated with multilingualism.
The public policy dimension touches on government decisions that aim to influence behavior. In the context of language, these could be laws and regulations affecting language use, such as those proposing English as the official language in certain U.S. states. Sociolinguistics and linguistic anthropology explore the social aspects of language, studying its use across different social groups and cultural processes, including how language can structure gender, race, and ethnic dynamics.