I am currently reading a chapter about dialect that distinguish dialects according to the alignment that is used in the dialect (alignment such as nominative-accusative, tripartite. etc)
I am confused with this sentence
In this pattern, S/A/P are left unmarked in the Sentence-Focus environment while overt marking for S/A (but not P) is obligatory when the subject (S/A) is focused.
What is the meaning of Sentence-Focus environment? thank you :)