As to the mannerisms of opera singers, it should be understood that there are a whole variety of different mannerisms or characteristics dependent on the type of opera singer one is speaking of. No one set of "mannerisms." A Wagnerian tenor is going to sound a whole lot different from a tenor more suited to Puccini, Verdi, or Rossini operas.

Wagnerian tenor, aria from "Lohengrin," in which he reveals that he is the son of Parsifal, and is a knight of the Holy Grail. ClICKY #1.

From "Il Trovatore" about a troubadour knight. He is about to be married to Leonora in the castle chapel when Ruiz runs in and tells him that the Count di Luna is outside the gates about to burn an old gypsy woman at the stake. Manrico, the troubadour knight, explodes in rage, revealing that the old woman is his mother, then calls his troops together to rush out of the castle, rescue the old woman, and kick some serious butt! (A couple of high C's at the end of the aria. CLICKY #2.

Lots of folk singers object to "vibrato," the slight variation in pitch. In most cases, this is not at all objectionable. In fact, a good vibrato should not even be noticeable unless you are listening for it. It lends "life" to an otherwise "flat" sounding voice (but not necessarily flat in pitch).   Many popular singers—and folk singers—do have this natural vibrato. The singer doesn't try for it. It should just happen naturally.

Oddly enough, perhaps, Richard Dyer-Bennet has very little vibrato.

Win Stracke, a classically trained (operatic) bass-baritone, did a beautiful, very creditable job on a whole variety of folk songs and ballads. But he understood folk songs. Where an opera singer is likely to go astray is when he or she includes a couple of folk songs in a recital, such as the performance of George London that I described above, but are otherwise not really familiar with the songs.

Don Firth