The particles of the Proto-Indo-European language (PIE) have been reconstructed by modern linguists based on similarities found across all Indo-European languages.
This is similar to modern languages; compare English He is above in the attic (adverb) and The bird is above the house (preposition).
The postpositions became prepositions in the daughter languages except Anatolian, Indo-Iranian and Sabellic; some of the other branches such as Latin and Greek preserve postpositions vestigially.
[1] Reflexes, or descendants of the PIE reconstructed forms in its daughter languages, include the following.
po[citation needed] Untranslated reflexes have the same meaning as the PIE word.
In the following languages, two reflexes separated by a slash mean: Two privatives can be reconstructed, *ne and *mē, the latter only used for negative commands.
The privative prefix *n̥- is likely the zero grade of *ne.
mi Adverbs derived from adjectives (like English bold-ly, beautiful-ly) arguably cannot be classified as particles.
In Proto-Indo-European, these are simply case forms of adjectives and thus better classified as nouns.
[8] The following conjunctions can be reconstructed:[9] †Placed after the joined word, as in Latin Senatus populus-que Romanus ("Senate and people of Rome"), -que joining senatus and populus.
There is only one PIE interjection that can be securely reconstructed; the second is uncertain.