Likewise, the correlation of subject and object with the semantic roles agent and patient, or subject with discourse topic, is at best only prototypical. Schematic characterizations valid for all instances have to be independent of specific conceptual content and discourse status. From the CG standpoint, they find a natural basis in the focal prominence of relational participants: a subject specifies the trajectory of a profiled relationship, and an object specifies the landmark. It is further suggested that this primary and secondary focal prominence resides in the participants being invoked as initial and subsequent reference points in building up to the full conception of the profiled relation (Langacker .1993, 1999c, 2001a, 2001b). This dynamic characterization meshes with Chafe's description of a subject as the ''starting point" for apprehending a clause (Chafe 1994).

Абзац большой (на всякий случай вставил его полностью), но меня интересует только focal prominence.
Помогите, плииз))