Linguistic Typology is the field that studies and classifies languages based on their functional and structural features. It is comprised by the analysis, comparison and classification of languages, and studies the structural similarities between languages regardless of their history.

There is evidence from linguistic varieties around the world that languages may not be entirely random from a sociolinguistic point of view and linguistic typology is certainly an area that tries to give explanations to these findings.

Typology has different tasks, including:

1. The classification of languages, which implies the construction of a system to order natural languages according to similarities among them.
2. The discovery of the mechanism of construction, a system of relationships among languages including not only the obvious mechanisms but also the latent ones.

The criteria used for dividing languages into different types depend on the purpose of the classification. For example, a typology based on word order will not necessarily correlate with one based on sound structure.

Usually, languages are classified according to three criteria: word structure (morphological), word order (syntactic) and sound patterns (phonological).

Morphology

It focuses on the way in which languages combine grammatical units, known as morphemes, within words.  It is the oldest established aspect of typology, with its origins in the 19 century. This method divided languages based on which degree the morphemes are fused together.

• Isolating or Analytics languages: where each morpheme tends to form a separate word.
• Agglutinating languages: in which several morphemes are juxtaposed within a word.

Syntax

It became the main criterion for classifying languages in the past quarter century. During 1960, researchers notices that of all the possible combinations of subject (S), verb (V), and object (O) within a sentence, only certain ones occur and they are not equally likely.

It is more common to find languages in which the subject comes first such as Turkish and English with the structure SVO, not that common to find languages in which verbs come first, such as Malagasy or Welsh (VSO) and even less common to find OVS structures. One example in these catgory are Hixkarayana, spoken in northern Brazil.

Phonology

There are some interesting studies based on types of vowel system and some hypotheses regarding consonants and sounds. However, this typology has received somewhat less attention than the others have.

Linguistic typology is an ever evolving area and the use and popularity of classifications have been changing from decade to decade. In fact, experts agree that it will be some more years before reliable methods of classifying languages are firmly established.