Whether a chord is borrowed from the parallel mode (modal interchange).
True when the chord is not diatonic to key but is diatonic to its
parallel key — e.g. iv, bVI, or bVII in a major key, or the Picardy
tonic and major IV in a minor key — and true for the Neapolitan, which is
counted as a borrowing of its own even though it belongs to neither parallel
mode. Two non-diatonic families are excluded: any other chord diatonic to
neither mode (those are chromatic, not borrowed), and, in a minor key, chords
explained by the altered minor forms (the major dominant and
raised-leading-tone chords), which are in-key alterations rather than
interchange even though they happen to fit the parallel major.
Whether a chord is borrowed from the parallel mode (modal interchange).
True when the chord is not diatonic to
keybut is diatonic to its parallel key — e.g. iv, bVI, or bVII in a major key, or the Picardy tonic and major IV in a minor key — and true for the Neapolitan, which is counted as a borrowing of its own even though it belongs to neither parallel mode. Two non-diatonic families are excluded: any other chord diatonic to neither mode (those are chromatic, not borrowed), and, in a minor key, chords explained by the altered minor forms (the major dominant and raised-leading-tone chords), which are in-key alterations rather than interchange even though they happen to fit the parallel major.