Language is a learned human behavior. All human societies have language. Languages share certain universal traits. The relationships between sounds and meaning are basically arbitrary. Language uses a finite set of elements to create an infinite set of possible sentences.
Language consists of sounds, forms and meaning.
People use language for a wide variety of purposes. Language use involves many psychological and emotional factors. Linguistic knowledge includes knowledge of sounds, forms and meaning. Language ability is innate in humans. Language ability is common to individuals with vastly different levels of intelligence.