Halliday & Matthiessen (1999: 447):
In rejecting both these views of language as distortion, we are not propounding an alternative version according to which language is a perfect match. What is wrong with all such conceptions is that they misconstrue the nature of a semiotic system — the fundamental relation of realisation to which we are always having to return. A semiotic system is not some kind of outer garment which may either reveal or conceal what is beneath. Rather, it is a transformation of experience into meanings, and each stratum within the system is construed by, and construes, all the rest. A “language”, in this sense, may be artificially constructed or engineered, like a scientific theory or a logic; but all such semiotics are ultimately related to natural language, and natural language is still an accomplice in their overall construction of reality.
Halliday & Matthiessen (1999: 465):
… if you treat language as distortion, you end up distorting language.