how to understand the deep structures of language

scientificamerican | There are two striking features of language that any scientific theory of this quintessentially human behavior must account for. The first is that we do not all speak the same language. This would be a shocking observation were not so commonplace. Communication systems and other animals tend to be universal, with any animal of the species able to communicate with any other. Likewise, many other fundamental human attributes show much less variation. Barring genetic or environmental mishap, we all have two eyes, one mouth, and four limbs. Around the world, we cry when we are sad, smile when we are happy, and laugh when something is funny, but the languages we use to describe this are different.

The second striking feature of language is that when you consider the space of possible languages, most languages are clustered in a few tiny bands. That is, most languages are much, much more similar to one another than random variation would have predicted.

Starting with pioneering work by Joseph Greenberg, scholars have cataloged over two thousand linguistic universals (facts true of all languages) and biases (facts true of most languages). For instance, in languages with fixed word order, the subject almost always comes before the object. If the verb describes a caused event, the entity that caused the event is the subject ("John broke the vase") not the object (for example, "The vase shbroke John" meaning "John broke the vase"). In languages like English where the verb agrees with one of its subjects or objects, it typically agrees with the subject (compare "the child eats the carrots" with "the children eat the carrots") and not with its object (this would look like "the child eats the carrot" vs. "the child eat the carrots"), though in some languages, like Hungarian, the ending of the verb changes to match both the subject and object.