Slip-up on particular area in speech (9)
I believe the answer is:
oversight
'slip-up' is the definition.
(I've seen this before)
'on particular area in speech' is the wordplay.
'on' becomes 'over' (I've seen this in other clues).
'particular area' becomes 'site'.
'in speech' indicates a 'sounds like' (homophone) clue.
'site' is a homophone of 'sight'.
'over'+'sight'='OVERSIGHT'
(Other definitions for oversight that I've seen before include "Inadvertent mistake" , "Neglect" , "Carelessness" , "A failure to notice, an omission" , "Shot giver due to unintentional omission" .)