It is true that a normal person can use language, but comparing this ability to eating, sleeping, or walking is misleading.
Literal
Normal person [subject-が] language [object-を] use thing [subject-が] can-do [quotative-という] [nominalizer-の] [topic-は] fact [but-だが], this ability [object-を] eating, sleeping, walking ability [with-と] compare [nominalizer-の] [topic-は] misleading.
A dense academic sentence comparing language to other abilities. ~というのは事実だが sets up an acknowledged truth before the 'but.' 誤解を招きやすい = 'easy to invite misunderstanding / misleading.' Heavy nominalization throughout.