I’d like to assume Estela’s *position* is the stratified context she mentions, of genre configuring register realised as language (and other modalities). This stratification is missing from much work on genre/language relations (within and without SFL), which has the effect of putting all the explanatory load on genre and language. One result is the ongoing battles over variations in genre that are really variations in field, tenor and mode. Another is the assumption that finding similar language patterns associated with different genres means that genres are somehow ‘mixed’.
 The "stratified context" model (Martin 1992), in which genre and register are misconstrued as context instead of language variants, derives from misunderstandings of both stratification and instantiation, as demonstrated in great detail here and here.
 This misrepresents Martin's model of stratified context. Genre doesn't "configure" register; on Martin's model, genre is realised by register. Martin posits genre and register as different levels of symbolic abstraction. In SFL theory, genre (text type) and register are the same phenomenon — functional varieties of language — viewed from opposite poles of the cline of instantiation.
 In SFL theory, register isn't "realised" as language; it is the culture-as-semiotic-system that is realised as language. Registers are (diatypic varieties of) language — different language variants that realise different context variants (situation types).
 In SFL theory, the relation between genre and language is modelled in terms of the cline of instantiation. At the system pole of the cline is language as potential, at the instance pole is language as text, and in the middle of the cline is language as genre.
 In SFL theory, "variations in genre" is linguistic variation according to text type, whereas "variations in field, tenor and mode" is contextual variation. In SFL theory, different genres (text types) realise different contextual configurations (Hasan) of field, tenor and mode features. In Martin's model, it is the opposite: different genres are realised by different field, tenor and mode features, with these features being misconstrued as register. In Martin's model, text type (genre) is realised by register, and neither are language.
 This is a non-sequitur. This assumption is not a result of ignoring Martin's confused model of stratified context. For the notion of 'mixed genres', see the previous post.