Language
Language is a system that consists of the development, acquisition, maintenance and use of complex systems of communication, particularly the human ability to do so; and a language is any specific example of such a system.
Public
In public relations and communication science, publics are groups of individual people, and the public (a.k.a. the general public) is the totality of such groupings. This is a different concept to the sociological concept of the Öffentlichkeit or public sphere. The concept of a public has also been defined in political science, psychology, marketing, and advertising. In public relations and communication science, it is one of the more ambiguous concepts in the field. Although it has definitions in the theory of the field that have been formulated from the early 20th century onwards, it has suffered in more recent years from being blurred, as a result of conflation of the idea of a public with the notions of audience, market segment, community, constituency, and stakeholder.
Public Administration
Public Administration is the implementation of government policy and also an academic discipline that studies this implementation and prepares civil servants for working in the public service. As a "field of inquiry with a diverse scope" whose fundamental goal is to "advance management and policies so that government can function". Some of the various definitions which have been offered for the term are: "the management of public programs"; the "translation of politics into the reality that citizens see every day"; and "the study of government decision making, the analysis of the policies themselves, the various inputs that have produced them, and the inputs necessary to produce alternative policies."