Soft mutation, lenition in Sindarin
Soft mutation, also called Lenition (=softening), is the most frequent mutation. It has many uses, it occurs after a series of particles, prepostitions and prefixes: typically those that either still end in a vowel or did so at an earlier stage.
A list with all those that cause lenition:
ab (=after, behind, following, later), prefix and preposition, originated as ‘apa’ in Quenya
adel (=behind, in the rear (of)), preposition, probably ‘atele’ in Old Sindarin
am (=up, above, over), preposition and prefix, ‘amba’ in Quenya
ath- (=on both sides, across), prefix, originated from the older ‘attha’
athra- (=across), prefix
be (=according to), prepostition, because it corresponds to the Quenya ‘ve’ it most likely means ‘as’ and ‘like’ as well.
dad (=down), adverb and prefix
di (=under, beneath), preposition
go-, gwa- (=together), prefix
i (=the), article
na (=to, towards, at, of, with, by), preposition
nu (/no) (=under), preposition
tre (=trhough), prefix
trî (=through), preposition
ú-, u- (=not, without), prefix
Adjectives following nouns are also lenited. (see post about adjectives)
Finally, a table with the mutations:
