A letter I translated, able to read and write (8)
I believe the answer is:
literate
'able to read and write' is the definition.
(I've seen this in another clue)
'a letter i translated' is the wordplay.
'translated' indicates an anagram.
'a'+'letter'+'i'='aletteri'
'aletteri' is an anagram of 'LITERATE'.
(Other definitions for literate that I've seen before include "Scholarly" , "Well versed in books" , "Well-read" , "Able to read and write" , "Relate it, being well read" .)