The American Sign Language sign for "vowel" is based on the British Sign
Language fingerspelling version of A E I O U.
Hold up your non-dominant hand with the fingers and thumb spread (like he number
5). Don't worry overmuch about the palm orientation, just hold the 5-hand up in
comfortable position with the palm generally facing toward the dominant side and
maybe backward a bit -- as if aimed at your dominant shoulder. Next run the tip
of the dominant hand index finger in a smooth semi-circle art around the tips of
the digits the non-dominant hand -- starting at the thumb.
Notes and
references:
See: https://media.spreadthesign.com/video/mp4/1/224347.mp4
and then contrast it with the quick and smooth movement in the second part of
this video: https://media.spreadthesign.com/video/mp4/40/425443.mp4 which helps
us see the difference between fingersepelling (in British Sign Language)
the individual vowel letters vs. signing "VOWELS."
Notes: