Milewski’s typology is a language classification system proposed in the 1960s by the Polish linguist Tadeusz Milewski. In this classification active and tripartite

Tripartite language

A tripartite language, also called an ergative–accusative language, is one that treats the subject of an intransitive verb, the subject of a transitive verb, and the object of a transitive verb each in different ways...

 languages were omitted because they were little known at that time.

Milewski proposed a division of languages into 6 groups, based upon consideration of 4 main syntactic relationships; these were:

1. the relationship of the experiencer to the verb
2. the relationship of the agent to the verb,
3. the relationship of the patient to the verb,
4. the relationship of the nominal attribute or predicate
   Predicate (grammar)
   There are two competing notions of the predicate in theories of grammar. Traditional grammar tends to view a predicate as one of two main parts of a sentence, the other being the subject, which the predicate modifies. The other understanding of predicates is inspired from work in predicate calculus...
   
    to the noun.

These criteria are interesting from a typological point of view because in many languages there is no difference between the sentence and the nominal phrase.

Milewski's typology can be employed to analyze languages with case marking but can also be used with those that use a fixed word order or a specific form of incorporation

Incorporation (linguistics)

Incorporation is a phenomenon by which a word, usually a verb, forms a kind of compound with, for instance, its direct object or adverbial modifier, while retaining its original syntactic function....

. For simplicity, the table below classifies casual languages in which the nominal attribute is marked with the genitive case

Genitive case

In grammar, genitive is the grammatical case that marks a noun as modifying another noun...

.

class	1	2	3	4	5	6
Experiencer to verb	a	a	a	a	a	a
Agent to verb	a	b	a	b	a	b
Patient to verb	b	a	b	a	b	a
Attribute to noun	c	c	b	b	a	a

The letters a, b, and c represent formal inflective markers specific to each language. For instance, "a" always represents the formal marker that signifies the experiencer, called either the "nominative" or the "absolutive" depending upon whether this morpheme marks the agent of the action (as in nominative–accusative languages) or the patient (as in ergative–absolutive languages).

As the table shows:

1. In languages of the 1st class, the experiencer and the agent are marked with the nominative case (the "a" marker) while the patient is marked with the accusative case (the "b" marker).
   This class is the most widely spread. Most nominative–accusative languages belong here.
2. Languages of the 2nd class inflect differently. The experiencer is marked with the same morpheme as the patient while the agent is marked with a distinct morpheme. In contrast to Class 1 languages, the "a" marker represents the absolutive while the "b" marker denotes the ergative (in Class 1 languages, the "a" marker denotes the nominative and the "b" marker the accusative).
   Most ergative–absolutive languages belong here.
3. Languages of the 3rd class could belong to nominative–accusative languages, i.e., the nominative marks both the agent and the experiencer (the "a" marker). Class 3 languages do not, however, contain distinct markers/cases for the patient and nominal attributes, which together share the same marker, which denotes genitive (the "b" marker).
   Examples of languages of the 3rd class are Indonesian
   Indonesian language
   Indonesian is the official language of Indonesia. Indonesian is a normative form of the Riau Islands dialect of Malay, an Austronesian language which has been used as a lingua franca in the Indonesian archipelago for centuries....
   
    and Hopi
   Hopi language
   Hopi is a Uto-Aztecan language spoken by the Hopi people of northeastern Arizona, USA, although today some Hopi are monolingual English speakers.The use of the language has gradually declined over the course of the 20th century...
   
   .
   It is interesting that marking the patient with the genitive is quite frequent in Slavic languages even if the accusative is usually applied in them just as in other European languages.
4. Languages of the 4th class could be considered ergative–absolutive languages insofar as they make no distinction between the experiencer and the patient, marking both with the absolutive (the "a" marker). Yet languages of this class are contrary to typical ergative–absolutive languages insofar as they mark both agent and nominal attribute as genitive (ergative-genitive, the "b" marker).
   Examples of Class 4 languages are the Inuktitut, Salishan languages
   Salishan languages
   The Salishan languages are a group of languages of the Pacific Northwest...
   
   , and Mayan languages
   Maya language
   A Maya language is one of a group of languages spoken by the Maya peoples of Mesoamerica.Maya language may also refer to:* Yucatec Maya language or Maya, a Mayan language spoken in the Yucatán Peninsula...
   
   .
5. Languages of the 5th class use the genitive not only for the nominal attribute but also for the agent and the experiencer (the "a" marker). The other case, called the accusative, marks only the patient (the "b" marker).
   The only language of this class mentioned by Milewski is Nisga'a
   Nisga'a language
   Nisga’a is a Tsimshianic language of the Nisga'a people of northwestern British Columbia. Nisga'a people, however, do not like the term Tshimshianic as they feel that it gives precedence to Coast Tsimshian. Nisga’a is very closely related to Gitksan...
   
   , a Tsimshianic language
   Tsimshianic languages
   The Tsimshianic languages are a family of languages spoken in northwestern British Columbia and in southern Alaska on Annette Island and Ketchikan. About 2,170 people of the ethnic Tsimshian population in Canada still speak the Tsimshian languages; about 50 of the 1,300 Tsimshian people living in...
   
   .
6. Languages of the 6th class use the genitive not only for the nominal attribute but also for the experiencer and the patient (the "a" marker"). The other case, the ergative, is used for the agent (the "b" marker).
   This group is not too numerous: Coast Tsimshian
   Coast Tsimshian
   Coast Tsimshian, known by its speakers as Sm'algyax, is a Tsimshianic language spoken by the Tsimshian nation in northwestern British Columbia and southeastern Alaska...
   
   , Tunica and Guarani
   Guaraní language
   Guaraní, specifically the primary variety known as Paraguayan Guaraní , is an indigenous language of South America that belongs to the Tupí–Guaraní subfamily of the Tupian languages. It is one of the official languages of Paraguay , where it is spoken by the majority of the population, and half of...
   
   belong here.