Harrison honestly believes he is communicating when he makes these noises. You'll notice that his eyebrows even move to further accentuate the point he is making. I have a few theories behind this squeak-speak of Harrison's. It is either some sort of high-pitched whale language or (more likely) baby dinosaur language. Either way, it is adorable. Those who don't know Harrison don't realize he is happy when he is making these noises, so I continually get strange looks from passersby who think I am just allowing my baby to cry, while watching him with a huge smile on my face.
After I filmed this little clip, I let Harrison watch it on the camera. He was quietly enthralled and then his face broke into an enormous grin - someone was FINALLY speaking his language!! He proceeded to squeal responses to the camera, relieved to finally have a conversation in his language.