Language (general)
A language is a system for encoding and decoding information. Determining what kinds of signals or symbols constitute language is not always a straightforward matter. Does the blossoming of a flower, whose color or scent signals to bees or birds to come and pollinate it, constitute a form of language? Does a skunk spraying constitute language, since it can certainly be said to be a form of communication? Are communications that involve, say, chemicals or pheromones part of some kind of language? Can we say that signaling behavior that is learned, rather than wired in, is language, whereas signaling behavior that is instinctive is not language?
The following article concerns language in all of its aspects. The definition of language - what counts as a language and what doesn't - is a difficult philosophical topic, deserving an article in its own right.
Human languages (Natural languages)
Human languages are also sometimes called natural languages, especially when there is a need to distinguish them from formal languages in mathematics or computer science. The science of studying human languages is linguistics, but linguistics is not the only scholarly area with an interest in human languages. The discovery of the oldest evidence of language, primarily via vestiges of early writing, falls under the pervue of archaeology or anthropology and also history. The mechanisms related to learning of human languages may be of interest in psychology and medicine due to its exercise of higher brain function. Computer scientists have been engaged in the study of human languages for the purpose of machine translation between different human languages.
Do animals have language?
Some animals communicate in a system which might be considered language, consisting either of calls or body postures used consistently for certain purposes and which are learned behavior. There are examples of multiple signals existing within one species, but signals are also sometimes used across species, such as when birds respond to chattering and tail waggles made by squirrels to warn of the presence of a predator. The question of whether animals have the capacity for language to a similar degree that humans have (even sign language) is controversial.
Formal, mathematical, and computer languages
The activity of computer engineering has produced numerous computer programming languages, and in fact they have created several subfields of scholarly research relating to them, such as formal languages and compilers. Mathematicians have expressed various mathematical formalisms that they describe as languages.