[thaumasiotes]

Huh. My instinct was that (in English), "solfège" is just the name of the collection of notes. (The same way that "alphabet" is the name of the collection of letters beginning "A B C D E ...".)

And interestingly enough, the English wikipedia page completely backs me up on that. https://en.wikipedia.org/wiki/Solf%C3%A8ge ("Solfège is a form of solmization, though the two terms are sometimes used interchangeably.")

However, the English wiktionary page gives no gloss other than "a method of sight singing". (More fully, "A method of sight singing that uses the syllables do (originally ut), re, mi, fa, sol (or so), la, and si (or ti) to represent the seven principal pitches of the scale".)

Merriam-Webster strongly supports the wikipedia definition, but it does note that "a method of sight-reading music" is an alternative, non-primary meaning.

In French, does solfège refer to any sight reading? A common way to sight-read vocal music is to sing the actual lyrics as opposed to the note names. And by far the most common way to sight-read piano music is to play it without saying anything at all.