Obviously, there are a lot of misconceptions about vibrato, what it actually is, and how it comes about in a singing voice. With most singers, including a number of folk singers, it just happens naturally, and it's not something one consciously sets out to learn how to do. It's just there. And it is perfectly normal.

Actually, vibrato—in any kind of singing—is not something most people even notice. Unless (like some people posting on this thread) they are intentionally looking for it as if it were a symptom of some dread disease or something. It's not. It's generally a sign of natural, healthy voice production.

Contrary to what appears to be popular belief, competent classical voice teachers rarely even address the matter of vibrato. Unless there is too much of it and it is wide enough to obscure the basic pitches of the notes being sung ("vocal wobble"). Nor do they try to instill vibrato into a voice. Been there. Years of voice lessons from two different classical voice teachers:   one, a former soprano at the Metropolitan Opera who also sang on the radio back in the 1940s, and the other an operatic baritone who became a teacher and choir director when he retired from the opera and concert stage. I don't even know if my voice has vibrato. I've never really noticed and no one has ever commented on it. I just open my yap and sing. I can rear back and bellow it out like an opera singer (bass), but because of the material I chose to sing (folk songs and ballads—traditional), I chose not to.

Vibrato? I presume I have some. Most normal singing voices do. Naturally.

Read the following:   Understanding Vibrato, by David L. Jones. Along with information on why vibrato happens naturally in a normal, healthy voice, it also examines when vibrato goes wrong, such as the "vocal wobble" and the "overly-fast vibrato."

It also explains why choir directors who insist on a "straight tone" could be putting their singers at risk. Read especially section (3), entitled The Straight Tone.

Here's an excerpt from an article on singing:

A true vibrato is a small fluctuation in pitch. The best demonstration of this is what good string players do, that is, rapidly move the left hand on the fingerboard so the pitch moves minutely up and down. On a bowed, and to a lesser extent a plucked, string instrument, this is done to lend a "warmth" to the tone that doesn't come from simply bowing the string. This is such a common practice that composers will write senza (without) vibrato on passages they don't want played that way, the implication being that the music should be played with vibrato at all other times.

The thing about singers is they can easily alter the pitch or dynamic of a note, thereby adding warmth to the sound of their voices by duplicating what string players do with their instruments.

Some singers do overdo it, but generally not the more successful classical singers. If you want to hear some real heavy-duty vibrato, you won't find it nearly as much among opera and other classical singers as you will from many of the pop singings from the 1920s and 30s. Try expatriate American singer Josephine Baker, for example CLICK. Or Edith Piaf? Frankly, as broad as their vibrato is, I would find their voices a bit tough to take without it.

Don Firth