I think Iternabe posted a link relating to Peter Feuchtwanger and Bel Canto. Perhaps the link below, or another that led me to the one below (thanks, Iternabe!):
http://peter-feuchtwanger.de/english-version/feuchtwanger-texts/bel-canto-on-a-percussion-instrument-/index.html
Within this discussion is the comment:
"It is obvious that the signs take on different meanings with different composers. Many musicians still believe that a sforzato sign always has a dynamic meaning whereas it is often an indication for subtly different timing. As soon as a pianist is confronted with a sforzato, he or she plays the relevant note or chord forte, con aggressione – even though in the context a pianissimo, con espressione would be much more to the point."
I'm so happy to see this - I was taught to play sforzato con espressione, with whatever dynamics I thought appropriate. I've recently come across various internet and method-book definitions of sforzato as being a strictly dynamic marking meaning ff, con aggressione, and was really puzzled about where the divergence was coming from. (Especially since IMO ff con aggressione often doesn't fit.) So I think this is a good lesson to not blindly accept what one reads, and instead listen carefully to where the music is leading you.
Separately, I think the discussion in the link gives a lovely sense of why it's so important to "sing" one's pieces when playing the piano...but it also touches on why one's discernment about certain aspects of singing affects the usefulness of singing the melody.