Not quite so fast… that’s pretty much how sign language works for humans too; you don’t sign each and every word/noun/adjective/whatever as you do when you talk. If you were to take a litteral translation of what the TRAINERS sign to the animals, you’d have a pretty similar transcript. If you read any books about these signing apes or watch any shows about them, you’d be well aware that they can do more than communucate “FOOD!” or “GO AWAY” or “TIME TO PLAY”. The part of one show I remember best is when Michael was (apparently) describing how his parents in the wild were shot and hacked up with knives when he was a baby. Don’t assume that a litteral translation of one language to another is a direct measurement of sophistication of either. When I was in Thailand, I learned that Thai for example is much simpler than english to use once you know it. I was told how to buy a bottle of water… two one-syllable words which directly translated into “buy water”. That doesn’t mean anyone who speaks Thai drags their knuckles on the ground and lacks the ability to think in more detail than that though.