Cross posted.

Also, Gibb Sahib, that, too, makes sense.

Key signatures are pretty much specific to music of the Western European tradition and are perfectly functional and adequate for notating the folk music of those countries (but speaking specifically of folk music of the British Isles and North America).

When a folk melody is modal, standard notation is also quite adequate for that as well--as Cecil J. Sharp noted when doing his collecting for his monumental English Folk Songs in the Southern Appalachians.

Many of the early collectors, when working in the field, assumed that these singers were unschooled and sometimes sang wrong notes, and they made what they thought were corrections. Sharp, on the other hand wrote down (in standard notation) what he actually heard, and discovered that many of the old modes were alive and well and were still being sung by traditional singers.

High marks for Professor Sharp!

Key signatures, plus any needed additional sharp, flat, or natural signs (called "accidentals") prove perfectly adequate.

Unless one were venturing into Indonesian gamelan music. Or Indian ragas, for example, in which case I would look up my old friend Nazir, who plays the sitar, and get him to give me a rundown on that kind of music.

Don Firth