Here's why:
* Phonetic Transcription: The word "whistle" is transcribed phonetically as /ˈwɪsəl/. The symbol /ə/ represents the schwa sound.
* Schwa Characteristics: The schwa sound is a very short, neutral vowel sound that is often found in unstressed syllables.
* "Whistle" Breakdown: In "whistle," the first syllable "whis" is unstressed, and the vowel sound is a short "u" sound (like in the word "cup"). This is the schwa sound.
So, the schwa sound in "whistle" is the short "u" sound in the first syllable, "whis."