Dear trombonegf: The trombones do not have to sing, I left the lyrics in the score since the piece was arranged from a piece for vocal choir. The lyrics can help to mark the sentences and the breath mark etc. The quartet includes a part for the soprano trombone (or the slide trumpet, please consider this one: http://www.free-scores.com/boutique/redirect-uk.php?clef=185884&acc=1) in Bb, the part might be too high for the alto trombone in Eb (it goes up to g''). The notation of the soprano part is non-transposing like the other trombone parts. It would be better to be notated with soprano C-clef (C clef on the bottom line of the staff) than the treble clef but the software does not have this clef. I am sorry if it is any confusing but the notation with treble clef in the soprano part is non transposing (practically in C) but the instrument to be played can be the slide trumpet in Bb, the normal trumpet in Bb or trumpet in C.
I am confused by your score. Are the Trombones supposed to sing? Also, I am confused by your use of the Treble Clef ...in "C" for the "Soprano" trombone. In the USA, Trombone parts are usually written in Bass clef and/or Tenor Clef (traditionally the highest were often written in Alto, as is the European tradition). In Europe today, OFTEN (but not always) Trombone parts are written in Bb in the Treble clef, much as Trumpet parts are written.
I would enjoy discussing these questions/idea with you.
