So a Sasquatch can't speak or understand spoken language..., WTF? Options

[HappyDaze]

OK, reading over the Sasquatch from the Runners' Companion, I'm at a loss as to why they can't speak and understand spoken language. This doesn't make sense for the following reasons:

1) Through use of the Mimicry power, Sasquatch are certainly capable of reproducing sounds - including speech - that they have heard.
2) Sasquatch use those sounds as hunting calls demonstrating that they can associate specific sounds for specific uses.
3) Sasquatch can understand and use sign language, meaning that the concept of language is not unknown to them.
4) Sasquatch can use AR to translate those 'sounds' made by others and see the 'sign' for what they mean or they can make a sign and hear a sound produced from it.
5) Sasquatch are every bit as intelligent as humans (and moreso than orks and trolls) with a Logic of 1/6 (9).

So, with the above points in mind, what's to stop a Sasquatch from associating those 'sounds' with a particular concept, and having them learn the association after a time without the AR (in effect, learning the language)?

Sorry, but as written, it seems like an idiotic "it's magic - they just can't" situation. Without a handwave, is there any good reason why they can't use spoken languages?