Sort of English inlet (7)
I believe the answer is:
estuary
I believe this clue is a double definition.
'sort of english' is the first definition.
(I've seen this before)
'inlet' is the second definition.
(I have seen 'Inlet of sea ' mean 'estuary' so perhaps 'inlet' could also mean 'estuary')
(Other definitions for estuary that I've seen before include "Weapon" , "Tidal mouth of a large river" , "Inlet of sea" , "A surety found in river's tidal mouth" , "A surety for river mouth" .)