Some scholars have proposed that play is connected with

The answer is metacommunication.  The explanation meta-conversation defines, for example, the situation, that two or more persons debate the way a certain conversation developed, especially how they preserved each other in that conversation. Meta firstly comes from the Greek language and means “higher” or “above”.

earliest

neumes above text

neumes

colored lines

neumes

4-line staff

f, c, or g clef

notes on 5-line staff with clef

mensuration (longas and breves)

time signature (perfect or half circle)

most recent

notes on 5-line staff

modern clefs

modern note values (whole, half, quarter, and so on)

modern time signature

italian words and abbreviations for dynamics and tempo

staccato, slurs, and so on