My students, who are learning as children, have a much easier time with solfege than I.

One little girl started her own country, and named it solfudgey.

When I learned it, numbers were taught instead of syllables. It was felt that numbers better convey the intervals. As a practical matter, it is something I never need or use. If a piece is unfamiliar, I play it. My choir seems to pick up from hearing better than from singing solfege. I suspect it was a method devised for singers who either couldn't or would never learn to read music. However, it is alive and well in our regional shape note singing. If you ever hear them learning new pieces of music, you will hear solfege.

Solfege is primarily a tool for facilitating accurate sight singing. I knew only a bit of it when I got to college, but (ahem!) years later, I can sight sing just about anything, provided I use solfege; I'm much more accurate that way.

I use solfege to sightread. While I'm already good at just plain sight-singing/reading, in general, I'm extremely accurate when I use solfege. And you can hum aloud while using solfege in your head!
It means that you don't have to have a keyboard, because you understand relationships between the written notes.

I don't see any reason why having perfect pitch should be a problem for transposed music, if you're basing your singing on solfege, rather than on A, B, C#, D... It's one reason why chant is so universal, and also why I think that people should make more use of reading scores in the alto and tenor clefs, and perhaps even the higher (that sits lower) bass clef.

My experience was like that of irishtenor. As music majors (though I was an instrumental major, and already sight-read well), we had a sight-singing class. It focused on syllables (in general), kodaly hand-signs, group & choral sight-singing, and then individual sight-singing examinations (each week or 2). We, of course, learned our "accidental" syllables, as well.

I love solfege. I think it's an excellent tool, and one in which all should strive to be "fluent."

Solfege has the glory and academic legitimacy of having a very historical pedigree. It is useful for all the reasons given above. It should be taught children very early in their musical educations. Some may use numbers, others, letters, but nothing has the academic authenticity of the solfege system.

That said, I learned it as an adult and it took me years to be able to use it fluently when reading chant. Being an excellent sight reader, I didn't really need an aid of any description to read intervals or learn a melody. I have never encountered a score that I couldn't hear in my head and sight read perfectly (an exception might be is Messiaen!). Still, after many years I can say that solfege has, at last, sunk in and become a feather in my cap.

I think that some are now bypassing solfege and using numbers or letters. I have noticed that even Fr Columba and some other chant scholars use the letter names of pitches rather that their solfege ones. This is fine for those who just don't readily assimilate the solfege system. It is, though, a little sad that in using other methods we are losing a system that has had universal currency in the music world for over a thousand years. This is enough to make one wish to share in such a tradition. It's really not all that hard!

(Plus, if you go to France or other countries and encounter a symphony in 'la mineur' you won't be able to know that that's A-minor.)

Highly skilled professional musicians who grew up playing piano or organ, such as many of the people, misunderstand the point of solfege and its benefits. Where it really helps is to bring a high level of sight-reading fluency to large groups of otherwise average people. And it only works that way if they are taught as children. You can't pick up solfege as an adult and expect to get very much out of it -- especially if you can already sightread with no problem.

Where it really helps is to bring a high level of sight-reading fluency to large groups of otherwise average people.

Adam, you nailed it. I've been teaching my sons solfege using the 4-syllable FaSoLa system and have been very happy with the results so far. I'd also add that it's helpful for someone like me who's not a great pedagogue to have a simple-to-teach system.

Solfege (with moveable Do/La-based minor) has transformed the way I approach sight-singing, both for myself and for all those I teach. For adult singers who already know how to read the treble/bass clefs but are unfamiliar with solfege, it can initially feel like "another thing to think about". However, with time and patience, it not only becomes easier, but a highly useful and systematic tool to learn a new piece of music, even if you have never heard it before.

Children -- and also adults who have never learned how to read music -- can make quick use of this tool, and they become increasingly more independent. I try to incorporate solfege warm-ups and exercises into all my choir rehearsals (I work with 8 choirs ranging from K-1 through semi-professionals). I'm trained in Music Mind Games and teach the "Daily Do" solfege exercise.

From https://www.musicmindgames.com/game/dictation-sight-singing/%E2%80%9Cdaily-do%E2%80%9D-major-section:

"Daily Do" is an original 67-note song using solfege and Curwen hand signs to sing intervals, major and minor triads and scales. It forms the basis for learning the staff, steady tempo, and scales.

Demo video of this exercise: https://vimeo.com/166148072"

When we have cantor coaching sessions, we are in a conference room without a piano/keyboard/organ. The group of singers (including some who tell me they have only ever "learned by hearing it first") learns Adam Barlett's Lumen Christ Psalm settings without ever hearing them played, by marking the solfege and then sight-singing them together.

Example here: https://www.dropbox.com/s/om2f8b5n9ed15rr/Solfege%20Psalm%2C%20Lent%203.JPG?dl=0

[wish I knew how to embed the image...sorry]

(Occasionally when I am making copies of something and know our rehearsal time will be limited, I mark them up like this before running the copies so that the singers can still use the solfege to learn the piece. It's highly beneficial for them to go through the process of figuring it out on their own, though, and then picking out the notes.)

The increased understanding and musical literacy it fosters are well worth the time invested. Spoonfeeding a melody might seem quicker in a single instance, but over time using solfege to form more capable singers is way more efficient!

Like many I learned solfeggio in college, so I know the fuss is real. It is a good schema for thinking about intervals, chords, and other sonorities theoretically. In practice it was tremendous for sight singing skills, singing with interference, and of course playing along with music of other cultures who use the solfa scale!