Halliday & Matthiessen (1999: 444):
Attempts to create an ontology without reference to language in general, or without reference to lexicogrammar in particular, seem to derive from the belief, familiar in the history of Western thinking, that language comes between us and a 'real' or scientific understanding of the world, that it somehow distorts our awareness of reality. There are two somewhat distinct versions of this belief.
The first is the notion that language distorts reality — or, as a variant of this, that language distorts our thinking (which includes our thinking about reality). This is extra-linguistic deception: language is deceiving us by the way it represents something else.
The second is the notion that syntax distorts semantics. This is intra-lingiiistic deception: language is deceiving us by the way one part of it represents another part.