Minimalist languages do not occur naturally. They represent one type of constructed language and have the design goal of reducing the number of available words in the lexicon.
A minimalist language can be either a priori or a posteriori. A priori languages are created independently of any existing language and often attempt to implement a philosophy. Many a priori languages organize their lexicon around some sort of taxonomy.
A posteriori languages have a lexicon based upon an existing language. These languages often attempt to simplify the perceived complexities of the base language's grammar or to create an easily understandable auxiliary language. A famous example of an a posteriori, auxiliary language is Esperanto, although it is not a minimalist language.
As stated, a minimalist language can be either a priori or a posteriori. Here, we will focus on a few examples of a posteriori, minimalist languages. Some examples are Newspeak and Toki Pona.
The minimalist, a posteriori language called Newspeak was created by George Orwell in his novel 1984. It is a posteriori because its lexicon is based upon an existing language, English, and it is a minimalist language because it attempts to reduce the number of words available in the vocabulary. This reduced vocabulary probably qualifies Newspeak as a philosophical language, too. The intent of the language's fictional creators was to control the concepts available for people to use for thinking.
The fictional language Newspeak was based upon an actual language called Basic English. Orwell opposed this experiment (after originally supporting it's goals of reducing the abuses of the English language perpetrated by politicians).
Another a posteriori, minimalist language is Toki Pona. This language was created in 2001 by Sonja Elen Kisa. It is an a posteriori language because its vocabulary is based upon words from several existing languages. Toki Pona is also minimalist due to it's remarkably small vocabulary size, weighing in at only one hundred twenty root words.
Toki Pona is also a philosophical language. The creator wanted to make a "happy" language and infused it with Taoist concepts. Many speakers of Toki Pona feel that the simplicity of the language forces them to break down their thoughts into smaller components. For instance, the vague term "heaven" has no root word equivalent in Toki Pona. Instead, one might say "big sky place".
It is in many ways an experiment with the Sapir-Whorf hypothesis. In a nutshell, the hypothesis states that characteristics of the language one is speaking affects one's thoughts. Speakers of Toki Pona are forced to build up concepts from the one hundred twenty root words. According to Sapir-Whorf, this would have an effect on their thoughts, probably causing them to focus less on specific labels (because these are absent from the lexicon) and more on the concept they are attempting to convey.
Minimalist languages can come in many types and sizes, but they all try to create a system that is capable of communication through the use of a restricted lexicon (and often a restricted grammar). At first glance, this might seem to be an obvious direction in which to move our cluttered and complicated languages. However, it should be noted that, while admirable and well-constructed, none of these minimalist languages has ever gained real popularity.
Perhaps after the initial glee at having such a small list of words to learn, the machinations required to express all but the most routine concepts causes people to return to more complex, but more precise languages. Perhaps it's something else entirely.