Here’s more on the importance of making a difference between short and long vowels :-)

SHIT /ʃɪt/ – 1. waste matter from a person’s or an animal’s body;

2. exclamation used to express anger or annoyance (INFORMAL, RUDE, VULGAR SLANG)

A SHEET /ʃiːt/ – 1. a piece of cotton used as a bed cover or 2. a sheet of paper – a piece of paper