X ran the hill up. There are general truths about all human languages and general tendencies in language patterns. Often, these tendencies are called universals. They help a linguist make preliminary hypotheses about the grammatical patterns in a language. Types of universals formal or substantive universals Formal universals deal with the grammatical patterns in languages, such as word order.
All languages have pronominal categories involving at least three persons and two numbers.
This and other universals about the existence of certain elements in every language are substantive universals. All six orders occur, although Object-initial languages are very uncommon. Linguists are interested in several types of relationships between languages. Typically such languages share many words, have similar sound systems, and have many grammatical features in common. Sometimes languages that are not genetically related also exhibit similar grammatical patterns.