Misrepresenting Halliday (1994) On Embedding (Rankshift)

Fawcett (2010: 265):

By far the most important type of embedding is the embedding of a clause as an element of a higher clause, or a clause as an element of a nominal, quality or quantity group — and so indirectly as an element of a higher clause. …

However, in the present grammar it is not the concept of embedding per se that leads to the richness of syntax, but the grammar's ability to fill many elements of many units by many other units. Sometimes this results in the embedding of a unit inside another of the same class (e.g., a clause within a clause, as described above), but often it is one class of group within another — and so one that would, in IFG terms, be at the same 'rank' as the higher unit.

Blogger Comments:

[1] To be clear, in SFL Theory, when an embedded clause serves as an element of a ranking clause, it is shifted to the rank of group/phrase, the rank whose units serve as the elements of clause structure. 

[2] To be clear, in SFL Theory, when an embedded clause serves as an element of a ranking nominal group, it is shifted to the rank of word, the rank whose units serve as the elements of group structure. The notion of quality or quantity group is unnecessary and inconsistent with  SFL Theory, as previously demonstrated.

[3] To be clear, in SFL Theory, a clause embedded in a nominal group serves as an element of a nominal group, not as an element of a clause — directly or indirectly. For example, in the following instance, the embedded clause that time forgot serves only as the Qualifier element of a nominal group, not as any of the elements of the clause:

[4] To be clear, from the perspective of SFL Theory, this "filling" includes both embedding and submodification; see the following post.

[5] Trivially, an adverbial clause is a class of unit, whereas a clause is just a unit.

[6] This is misleading, because it is untrue. In IFG terms, a (rankshifted) group that is embedded in another group is not at the same rank as the (ranking) group in which it is embedded. The embedded group is shifted to word rank, as explained in [2] above. This is one reason why the term 'rankshift' is more informative than the term 'embedding'.