I listened to John McWhorter’s course The Story of Human Language. ‘Language’ primarily refers to spoken communication. Written language is considered a relatively new invention; how people write is quite distinct from how they actually speak, even within the same language. A person who speaks in paragraphs is very odd, suggests McWhorter.
The story of language change is all about how sounds evolve over time. Vowels shift, consonants merge. Sometimes sounds get ‘rebracketed’ — word boundaries of commonly used phrases change. Certain combinations of syllables are simply hard (like trying to pronounce ‘February’) and over generations, they morph into something simpler. Certain sounds are in constant danger of disappearing, like the ‘h’ at the start of a word. Word order occasionally flips from subject-object-verb to subject-verb-object, or the other way around. Grammar is, to a degree, optional — a lot of information is derived from context.
Many modern languages have so-called high and low varieties, the high variety being what is considered ‘proper’, and the low variety being what is normally used by everyone. This phenomenon is called diglossia. A newcomer learning a language may mistakenly learn the high form, use it in ordinary speech, and get laughed at. The high form is what’s taught in schools, the low form is what you pick up through everyday experience. Strangely, the low form is generally not considered fit to be formally taught.
Languages don’t really exist, it turns out. All you have is bundles of dialects, each one a little further removed from the other. Language distinctions are drawn by geopolitics; certain languages are even closer to each other than certain dialects. All you have is a continuous evolution of dialects into others as they get separated by geography. These dialects keep evolving further and further until they start looking quite different from the original.
When people of different tongues are forced to interact with each other on a temporary basis, they may create an ultra-simplified language that enables a minimal degree of communication. Such languages are called pidgins and not expressive enough to be considered full-fledged languages. But when the arrangement becomes more permanent over multiple generations, these stunted languages may then develop into new ones called creoles.
The Story of Human Language is an exciting and beautifully narrated tale; I highly recommend listening to it.