Here's why:
* Short vowels are typically pronounced quickly and with a single sound. In "tag," the "a" makes a short, sharp sound similar to the "a" in "cat" or "hat."
* Long vowels are usually pronounced more slowly and can be represented by a single vowel followed by a silent "e" at the end of the word (like "mate") or by a vowel digraph (like "rain").
Let me know if you have any other questions!