Koko can control her voice and breath in novel ways; it would be interesting to see if this is true for other gorillas.
Koko demonstrates her ability to control her vocalizations and breath in two different situations. First, she demonstrates a “Blow-Test” as a welcome gesture during her meeting with Mister (“Fred”) Rogers, vocalizing “who” after Penny and Mister Rogers do. Then, in a separate sequence, she demonstrates a “Blow-Out” — blowing out the candles on her 40th birthday cake. Such capacities in non-human great apes were previously thought by researchers to be very limited.