Haven't been closely following this thread, but should have. I totally agree with Gumshoeye and Norseman about the cartoon, Totally silly.
BF does talk, no question in my mind about that. If you hear one talking just as it passes a sound dish, 50 feet away, and your are listening to the amplified sounds with headphones at 2 AM in the boondocks, it's not something you will soon forget. When, a few seconds later, it's looking into the back window of a camper shell where you've been sleeping, and its about 3 feet from you, the sight and sounds are never forgotten.
If you listen to the Sierra Sounds CD closely, you will hear one of the big males ask a question of the men, and repeat it when the men don't respond. The question to the reader is; what is the question the BF is asking? :-)
They are a clan of humans, but not modern humans. They will live, forage and eat in a particular area until modern humans or natural disasters force them to leave. The will abide human presence as long as we do not interfere with their hunting/foraging, or try to ambush them - with gun or camera - at their cold water drinking sources in hot weather, or try to approach the family's bedding site day or night. Otherwise, they are simply having a little fun when they mess with folks, especially late at night. If anyone spends enough time in their territory, both day and night, and you show no fear of them, and show respect for their rules, one or more will eventually allow you to briefly and clearly see them.
They realize that us humans are more advanced than they. In the back of my mind I believe that natural instincts urge them to capture and mate with Homo sapiens to improve their blood lines. It may be that they think that by kidnapping children, removing their clothing and carrying them into the boonies, they hope to raise them so that the children can then teach them the things that we know. They don't (or can't) understand that our children can't survive in the wilderness as their's do. (As mentioned, this paragraph is absolutely without a whit of evidence, and solely a thought that often enters my gourd.)