Possible Clues:

• Sound heard twice in “Aruba”
• Kitsch outfit dismissed with a sound
• Either end of amoeba?
• It begins "again"
• Beginning or end for Alexa?
• Unstressed vowel we analysed originally after school
• Sound represented by an upside-down 'e'
• Sound like a faulty chainsaw, cutting out first in ...
• Most common vowel sound in English
• Central vowel sound