"chords with modes" is just an informal way of saying "learn the meaning of diatonacism". you could call it chord funcionality or chord/scale relationships.


for instance, the ever-popular I-IV-V will change depending on the notes of the scale/mode itself. for instance, the dorian mode is rooted with a minor tonic (i) but unlike the natural minor (aeolian) we don't find a minor 4 chord (iv) in the scale. because of the raised 6th note that characterizes the dorian mode, we find a major 4 chord (IV). subsequently, the flat 7 scale degree makes the 5 chord minor instead of major. in a diatonic sense, the 7th note of a minor scale is always raised to give a leading-tone sound that creates tension. when tooling with modes, we come across the minor 5 chord sound (v) that lends us ambiguity and other avenues of musical creativity.


but about exotic scales and their ties to cultural and geographical differences in music, the scale is not always the case. that is a bit of a misnomer, considering jazz musicians were simply copying classical composers such as mahler and debussy. just as jazz music didn't bring about the invention of extended chords, exotic scales did not bring rise to culturally-identifiable music. certain characteristics will still be evident to you when you hear a major pentatonic played in the style of a wooden flute, with trills and repetition on one octave. you will recognize and adhere to the traditional japanese sound of the iwato scale. but for the most part, you have to make the scales work with your ideas and your creativity, not the other way around. don't tell yourself that just because you like rock and metal that all you need is a harmonic minor scale.