Yeah, that comment didn't really make sense to me either.
I'm fluent in ASL, and I have a working knowledge of BSL. What I can tell is that ASL is more conceptual than BSL. BSL tends to track the English language more closely. For example, ASL will have one sign that expresses an entire sentence, but BSL will most likely have individual signs reflecting the individual words in the sentence. (This is not always true, of course.)
All of sign languages depend primarily on gestures and facial expressions.
I'm fluent in ASL, and I have a working knowledge of BSL. What I can tell is that ASL is more conceptual than BSL. BSL tends to track the English language more closely. For example, ASL will have one sign that expresses an entire sentence, but BSL will most likely have individual signs reflecting the individual words in the sentence. (This is not always true, of course.)
All of sign languages depend primarily on gestures and facial expressions.