Here's why:
* The vowel sound in "light" is short. It's pronounced with a short "i" sound, similar to the "i" in "hit."
* Long vowel words typically have a long vowel sound. This means the vowel sound is pronounced as its name (e.g., "a" in "cake," "e" in "tree," "i" in "bike," "o" in "go," "u" in "cube").
Therefore, "light" is not a long vowel word.