Most Australian languages do not have adpositions (prepositions or postpositions). They have a system of suffixes (or, in some languages, enclitics) that mark the function of a phrase in its clause. Only in some of the languages that have developed both prefixes (with bound pronouns) and noun classes (with noun classes being marked on the 3rd person pronominal prefixes) has the case marking of NPs in core syntactic functions been lost, or is it being lost; see §10.7.1. Generally, there are still suffixes to mark non-core relations. Adpositions are used in just a sprinkling of languages, mostly of the prefixing type. The use of prefixes to mark the syntactic function of an NP is rare in Australian languages; those languages in which it does occur are discussed in §10.5 and §10.7. (Suffixes which do not mark syntactic function but simply supply semantic modification are briefly mentioned under (g) in §3.3.6; and dual suffixes are mentioned in §4.2.6.)

It is useful to recognise fourteen types of syntactic function, covering functions of a phrase within a clause, and also of a phrase within a phrase; these are introduced in §5.1. It should be noted that there is a degree of similarity – in meaning and function – between suffixes that are given the same label in different languages, but never complete equivalence.

No language has as many as fourteen distinct case-type suffixes or enclitics.