Language is unique to each person and its use will inevitably change from place to place.
In order to set a foundation, and a benchmark, that will hold language true to its original and proper use and context, various countries, organizations, and academies develop their own "language planning" approaches.
This being said, language planning refers to the process of defining and safeguarding the proper use of a specific language so that the true meaning of its words, within their proper context, is preserved. The purpose of this serves a basic premise: although language is flexible and interchangeable, its original use, format and meanings should be protected and put to use in the proper time and place, as required. It also helps solidify the identity of a group which, ultimately, helps the group in the process of communicating with others.
Think about this: language is not used the same way everywhere. There is medical language, legal language, educational language, business (administrative) language, and even media and entertainment language, just to name the basics. The process of language planning, although looks like an impossible task, aims to provide some guidelines as to the proper use of each.
There are three ways in which language is planned: textually, functionally, and formally.
The textual study of language, textual planning refers to how language is used within a specific context, and how it could most effectively have fluency and be used to transmit information in written form.
The formalities of language in corpus planning relates to standardization of language usage and literary usage, for instance in grammar and vocabulary. That is to say that language will be standardized through such things like manuals and dictionaries.
The language activity and its function from country to country is best studied through status planning. A good example of status planning would be Spain: some minority groups in Spain have acquired legal status as citizens. This means that they will now bring to the country their own linguistic additions as they are found in their unique dialects. Status planning will make policy about language purity and the inclusion or exclusion of any influence from foreign dialects.
This latter planning could also fall under the umbrella of acquisition planning, which is second language acquisition as it occurs from one group to another and teaching primary or secondary language acquisition.
Therefore, since language is such a complex and rich communication tool, efforts are made to preserve it. Language planning is done in a case by case situation, and it takes a long time to gather and triangulate a significant amount of longitudinal and phenomenological data. Therefore, it is a process that requires expertise and a careful consideration towards every existing variable.