Latin/Assimiliation of Consonants
I came across the following phrase in Latin:
Fugit inreparabile tempus.
I have seen the the word inreparabile spelled irreparabile. Are they both correct? Is one the alternative form of the other? And if not, which one is correct?
There are a number of consonantal clusters that are seen in both their unassimilated and assimilated forms. "irr-/inr-" is one of these. In most Latin dictionaries you will see a alphabetical listing such as the following: "irr- see inr-". The difference is not merely a spelling difference, but reflects alternative pronunciations.
The unassimilated (root) form is "in" (from the preposition or, as here, the privative, meaning "not") plus a word beginning with "r" ("inreparabile"). There is another form, in which the "n" is assimilated to the following "r", for reasons of euphony or ease of pronunciation ("irreparabile"). Both are correct.
A similar principle of assimilation is seen in forms such as "eundem," which exists with "eumdem". In the instance of "eundem", for reasons of euphony or ease of pronunciation, the labial consonant (made with the lips) "m" is assimilated to the dental consonant (made with the teeth) "n" to correspond to the following dental "d".
For more information and examples, consult Allen & Greenough's New Latin Grammar, Section 16.