This is not the process we see for stratification, possibly motivating Halliday to consider the description of language at each stratum to be a description according to different types (Halliday 1981 [2005]).
This concept met with considerable resistance amongst philosophers but has had a colossal influence on linguists, who have tended to see it as a useful concept in the description of language (see Huang 2007, ch. 7).
As Halliday has often reminded us, the description of language is always open-ended, and more can be said on this topic e.g. about the aesthetic function of calligraphy, or the visual lay out of graphic material and so on.
Though Marty did, as already indicated, focus much of his work on the description of language as it is, his earliest work (Marty 1875) was concerned with the origin of language.
How can the data from speakers with aphasia add to this theoretical description of language and gesture relationships?
This work typically brings a quantitative dimension to the description of languages by including information on the probability with which linguistic items or processes occur in particular contexts.
These studies became some of the earliest systemic studies on the description of languages other than English.
For the past two decades, the description of languages other than English, in general, and language typology, in particular, has increasingly garnered much interest in systemic functional linguistics (SFL).
In recent years, the various editions of IFG (Halliday 1985, 1994; Halliday and Matthiessen 2004, 2014) and Matthiessen's (1995) LexiCart have provided comprehensive models and guide for the description of languages other than English.
Despite the importance of phonology to any general description of language, the editors note that this is the first collection focusing on phonology within a SFL framework in the last twenty years.
