Adpositions is the term combining prepositions and postpositions as they play similar role in the sentence. English language has only prepositions, but in many Uralic languages there are mostly postpositions and very few prepositions. Classical Black Speech is considered similar to them in that feature, but Debased Black Speech is closer to English. Nûrlâm supposed to be in between these two opposite concepts of language.

In Nûrlâm's dictionary there are approximately twice more amount of postpositions than prepositions, but postpositions are divided into two categories: clitic and standalone. Clitic postpositions take the role of case suffixes, standalone postpositions usually refer to place or orientation in space and consist of one syllable only, and prepositions are either two syllable long or refer to time. Standalone postpositions and prepositions are used together with noun in corresponding case (clitic postpositions), which should be memorized. Some words are used both as prepositions and as postpositions depending on meaning.

Adpositions may also serve as verb's derivational suffixes (as in Finnish, Turkish or Hurrian) or prefixes (similar to Latin, German or Russian).

For list of clitic postpositions see article about grammatical case. They are functioning as case suffixes but usually translated into other (Indo-European) languages as prepositions. Attaching a clitic may change declension class of a word according to declension class of their own.

Standalone postpositions are single syllable short words usually describing place, direction or position in space. Some of them are used together with specific case expressed with clitic postpositions, thus requiring memorization. Many of these postpositions may be used as standalone adverbs. But please not that many words for directions are actually nouns, so not listed here.

Prepositions are used for referring time in adverbial constructions, but some polysyllable words specify position.

Black Speech doesn't seem to have complex (two or more word) adpositions or has very few of them. Such English words as “into”, “within”, “in front of” etc. are all translated with one corresponding word. Some of compound prepositions actually belong to different words (e.g. verb and noun, see next chapter of this article).

Beside the fact that some adpositions are used both as pre- and post-positions they may also be treated as other lexical categories. Usually the adpositions belonging to verbs are technically adverbs or particles, which also follow the words they describe similarly to postpositions, and some of them are attached to verbs as clitics or prefixes. Locative case postpositions and some standalone (like “ik” = before) form adverbial phrases together with nouns. These words may also connect together two clauses with different verbs, thus becoming conjunctions. So it can be hard to distinguish adpositions from other lexical categories. Anyway adpositions are never used as stand-alone member of sentence, only together with other words. Some words may belong both to adverbs when used stand-alone, and to adpositions when noun is taken together to form adverbial phrase.

Black Speech has following stages of language evolution in using adpositions.

1. Classical Black Speech is considered to have only postpositions and majority of them are clitic.
2. Nûrlâm further separates standalone and clitic postpositions by reducing number of cases, some postpositions became prepositions (usually referring time).
3. Cases' quantity continue to drop. More postpositions become used as prepositions dithering the edge between them.
4. More prepositions and standalone postpositions becoming used with Accusative case (with zero ending).
5. In modern colloquial (Debased) Black Speech all adpositions became prepositions together with denying category of grammatical case.

• Wikipedia article