In American English, unstressed syllables are usually shorter than stressed syllables. Because unstressed syllables are said more quickly and less precisely, the vowel sound in these syllables is usually reduced to a more neutral sound known as the “schwa”. The schwa is pronounced “uh”, as in the word “a” (e.g., a book). It’s the most common sound in English because it’s used in the valleys of intonation. The word “today” is spoken as “t-day”.