Like daughters, speaks about youth (5,4)
I believe the answer is:
salad days
'youth' is the definition.
(I've seen this before)
'like daughters speaks about' is the wordplay.
'like' becomes 'a la' ('a la' can mean 'in the way of' in French).
'daughters' becomes 'dd' (a genealogical abbreviation for daughter repeated).
'speaks' becomes 'says' (to say something is to speak).
'about' is an insertion indicator.
'ala'+'dd'='aladd'
'aladd' inserted inside 'says' is 'SALAD DAYS'.
(Other definitions for salad days that I've seen before include "Period of youthful inexperience" , "inexperienced youth" , "when one is young?" , "Period of youth and inexperience - on lettuce diet?" , "times when she was young" .)