The soldier's shoulder surely hurts!
S-W-Ch

There's a sandwich on the sand which was sent by a sane witch.
Sh

Shy Shelly says she shall sew sheets.
Sh-S-Sl

She sees seas slapping shores.
Si-Sea

Six sick sea-serpents swam the seven seas.
Si-Sh

The sixth sick sheik's sixth sheep's sick.
Si-St

Six stick shifts stuck shut.
Sl-Sh

I slit the sheet, the sheet I slit, and on the slitted sheet I sit.
St-Sk-Th

A skunk sat on a stump and thunk (thought) the stump stunk, but the stump thunk the skunk stunk.
Sw

Swan swam over the sea. Swim, swan, swim! Swan swam back again. Well swum, swan!