Here's why:
* Short vowel sounds are typically represented by the vowel letters (a, e, i, o, u) in a closed syllable (a syllable that ends in a consonant). Examples of short vowel words include: cat, bed, pig, hot, and cup.
* The vowel sound in "flag" is a long "a" sound. It is a long vowel sound because it is followed by a consonant-vowel-consonant (CVC) pattern ("ag"). This pattern often indicates a long vowel sound.
Therefore, "flag" is a long vowel word.