There is no widely established specific sign for "billion."The best way to sign or express the concept of "billion" is going to depend on your situation. See the discussion below.
In a message dated 7/15/2014 9:37:33 A.M. Pacific Daylight Time, A student writes:Is the sign for BILLION tapping the right B hand on the open flat left hand twice?
And TRILLION 3 times?
Dear _______,
Technically if a person were to follow the "tapping" approach to billion and trillion you'd have to tap BILLION 3 times and TRILLION 4 times since "MILLION" is tapped twice and THOUSAND is tapped once.
But realistically most of the time we don't do that.
Usually we just spell BILLION. Remember that Deaf people tend to spell a word almost as fast and sometimes faster than it can be signed. I and most of my friends spell "billion" faster than we can do three taps on our non-dominant palm.
Sure, sometimes we do a sign for BILLION that taps the non-dominant palm in three different places with the fingertips of the bent dominant hand -- starting closest to the heel of the non-dominant palm, then in the center of the palm, then on the fingers area.
For what it is worth, when being spelled at high speed some of the letters tend to get mushed or dropped. For example it often looks like "billin" (the "o" gets dropped). Ha! I just noticed that sometimes when I spell BILLION I tend to jut my head a bit forward and an inch or two to my dominant side as I spell. (Sort of like what a person might do with their head when watching a fast car zoom past.) I'm not saying many people do that, I'm just pointing out that signing is complex there are a "million" (heh) little ways in which we modify things to make them clear.
- Dr. Bill