There are 5 vowels in the English alphabet: A, E, I, O, and U. These are the standard vowel letters taught in English because they commonly represent vowel sounds in written words.
The modern English alphabet contains 26 letters. After counting the five vowel letters, the remaining 21 letters are usually described as consonants, although English spelling is more flexible than that simple division suggests. The letter Y can act like a vowel in words such as “myth” and “happy,” but it can also act like a consonant in “yellow.”
Vowel letters and vowel sounds are not exactly the same thing. A single vowel letter can represent different sounds, and several letters can combine to make one sound. For example, the E in “bed” and the E in “these” sound different. The letters W and Y can also have special roles in certain words, but the standard answer to this alphabet question remains five.