sphere
e is the unstressed vowel in Febuary
The unstressed vowel in "skeleton" is the first "e".
The letter "e" in "dangerous" is unstressed.
The unstressed vowel in "controversy" is the schwa sound represented by the letter "o" in the second syllable. The schwa sound is a neutral vowel sound that is often found in unstressed syllables in English words.
The unstressed vowel in "Listener" is the schwa sound, represented by the letter "e".
The unstressed letter in "temperature" is the second "e."
e
The unstressed vowel in "interrupt" is the second 'e' sound, represented by the letter 'e' in the word.
The second "e" in vegetable is the unstressed one. It is pronounced as a schwa sound (/ə/).
It depends on your dialect. In American English the second 'e' is unstressed and pronounced as a schwa (like the 'a' in "about"). In British English both the second 'e' and the 'a' are unstressed; in fact the 'a' practically disappears.
e
No, the word "marvelous" does not have an unstressed "e." The stress falls on the first syllable, "mar-."