Here's why:
* The vowel "e" in "television" is in a closed syllable. A closed syllable ends with a consonant. The "e" is followed by the consonant "l," making it a closed syllable. In closed syllables, the vowel sound is typically short.
* The "i" in "television" also has a short vowel sound. It's followed by the consonant "v."
Therefore, the word "television" has two short vowel sounds: tel·e·vi·sion.