The article says 

"Sue Savage-Rumbaugh has observed Kanzi in communication to his sister. In this experiment, Kanzi was kept in a separate room of the Great Ape Project and shown some yogurt. Kanzi started vocalizing the word "yogurt" in an unknown "language"; his sister, who could not see the yogurt, then pointed to the lexigram for yogurt.[5] ".

Now in this case, TG, there is a clear misrepresentation of the source, which reads 

"In one experiment she described to me, she placed Kanzi and Panbanisha, his sister, in separate rooms where they could hear but not see each other. Through lexigrams, Savage-Rumbaugh explained to Kanzi that he would be given yogurt. He was then asked to communicate this information to Panbanisha."Kanzi vocalized, then Panbanisha vocalized in return and selected ‘yogurt’ on the keyboard in front of her,"Savage-Rumbaugh tells me."

These accounts are substantially different, as you can see. 

In the source, S-R explains to Kanzi. through lexigrams, that he 'would be given' yogurt - in the article, he is 'shown' the yogurt.

In the source, Kanzi is asked to tell Panbanisha that he would be given yogurt, in the article he isn't.

In the source, Kanzi simply vocalizes; in the article, he vocalizes in an "unknown 'language'".

Why is the wiki article simplified in this way ? Because the claims in the source are incredible. As far as I know, lexigrams do not include words such as 'would', so S-R can't tell Kanzi that he 'would' be given yogurt. Secondly, Kanzi is supposed to understand 3000 spoken English words (that's according to the wiki bonobo article, which references (guess what) the same Raffaele article we're talking about), so why does S-R need to use the lexigram at all ?

More importantly, both the article and the source refer to this 'experiment'. It would be nice to know the details of this experiment, which might describe how many objects Kanzi was shown, how often he vocalized, and how many times Panbanisha responded with accuracy, and so on.

I can't find this experiment. Tonight I contacted the Great Ape Trust, where S-R works with Kanzi, and asked for the reference. I'll let you know what they say. I'll leave off amending the article in the meantime.