Quick note: I've gone over to English to accomodate a couple of American friends. We'll see how long it lasts.
The use of pictorial language to denote emotion and/or tone of voice is hardly new in comics storytelling. "Astérix", for example, excels in it. Especially when it comes to depicting the character of sound, it is very innovative because it uses once sense modality – vision – to depict another – sound/hearing.
The creators of "Zits", Jim Borgman and Jerry Scott, are often visually creative in their storytelling, and here they have melded two concepts – the modern-era free choice of different ringtones for different people and the use of visual language to connote personal characteristics – in an innovative and quite funny manner.I'd say that "Zits" is probably the brightest spot on today's comics page.
(Also note that it isn't just different sounds that Brogman/Scott are depicting with their iconography, but also the somewhat more abstract concept of personal characteristics.)