Here's why:
* The vowel sound in "wig" is the same as the vowel sound in "big" and "dig." These are all long "i" sounds.
* Short vowel sounds are typically represented with a single vowel letter and are often followed by a consonant. For example, "cat," "dog," "hop," and "sun."
Therefore, the "i" in "wig" is a long vowel sound, not a short vowel sound.