Here's why:
* Short vowel sounds are typically pronounced quickly and are often found in words with one syllable.
* Long vowel sounds are usually pronounced like the vowel's name (e.g., "a" in "ate") and are often found in words with two syllables or when a vowel has a silent "e" at the end.
In the word "pin," the "i" is pronounced with a short vowel sound, similar to the "i" in "sit" or "pig".