rippling, gurgling, whisper, rustling, and hushed.
hallow
Winding, mellow
Mellowed is a verb. It's the past tense of mellow.
He became more mellow as he aged.
River Severn (sounds like seven)
Are you thinking of the River Tigris.
The Amazon river dolphin, or pink river dolphin, Inia geoffrensis, does make sounds and calls.
The Mississippi River
Indus river
The river Wye (it runs along the Welsh/English border)
The letter s.
"Red River."
me screaming