Well, the problem may be more complicated than writing to stay within the typical ranges for Soprano, Alto, Tenor and Bass. Truth be told, an arrangement may be written sticking to those guidelines and still be uncomfortable for the singers to sing. That's because of something called TESSITURA.

For example, the Soprano part towards the end of Handel's "Hallelujah" Chorus dances on Treble D for many measures at Forte. Treble D is right on the PASSAGIO for a Soprano. Lots of repeated notes on Treble D can get very tiring. She would prefer notes in that part of her register to be soaring on long open vowels with no busy lyrics.
Music written that looks like it lies perfectly within the singer's range, may actually be deceiving. A Tenor's speaking voice may fall right around Middle C. He may feel perfectly comfortable singing "speaking lyrics" on those notes that if written in Treble clef are right around Treble C. So, because those notes are well within the Soprano range, they should feel comfortable for a woman to sing, too. Right?
Not necessarily. For a Soprano, those notes fall right on her PASSAGIO. Those pitches are NOT in her "speaking" range, and depending on how fast the lyrics are, they surely require a lot of jaw action to form the consonants. This can definitely cause strain and discomfort.