When does a vowel sound like itself?

This is a tricky question because it depends on what you mean by "sound like itself."

Here's a breakdown:

* In isolation: When spoken in isolation, vowels generally sound like their own "self." This is the most straightforward way to think about it.

* In words: When in words, vowel sounds can change depending on the surrounding letters, the stress of the word, and other factors.

Examples:

* The vowel "a" in the word "cat" is different from the "a" in "father". This is because the "a" in "cat" is a short vowel sound, while the "a" in "father" is a long vowel sound.

* The vowel "i" in the word "hit" is different from the "i" in "machine". This is because the "i" in "hit" is a short vowel sound, while the "i" in "machine" is a long vowel sound.

So, to answer your question more specifically:

* Vowels sound like themselves when spoken in isolation.

* Vowels can sound different from themselves when in words due to phonetic rules and context.

Let me know if you'd like me to explain any of these vowel sounds further!