Form of English inlet (7)
I believe the answer is:
estuary
I believe this clue is a double definition.
'form of english' is the first definition.
(Estuary English is a type of English accent)
'inlet' is the second definition.
(I've seen this in another clue)
(Other definitions for estuary that I've seen before include "River outlet" , "Weapon" , "flower going into the sea" , "Wide river-mouth" , "Inlet of sea" .)