Your article claims that this shouldn't be possible, because according its author, humans are incapable of developing the necessary "lexicon". Literally, the author states:

>But here is what we are not born with: information, data, rules, software, knowledge, lexicons, representations, algorithms, programs, models, memories, images, processors, subroutines, encoders, decoders, symbols, or buffers – design elements that allow digital computers to behave somewhat intelligently. Not only are we not born with such things, we also don’t develop them – ever.

(emphasis mine)

In other words, that author claims that humans never develop lexicons! I'm inclined to say that makes them an unserious thinker. (Note: I believe that this article has many issues, but instead of going through it carefully I just chose to highlight a single issue that seemed especially vivid to save time.)

Why is the text channel relevant? It helps us isolate the cognitive capabilities of the system. Imagine a bird and a model plane which had identical flight performance in terms of various specs: top speed, acceleration, banking, etc. Under the hood, the bird and the model plane could work very differently. From a practical perspective, it might not matter.