This classic line from the movie Jerry Maguire brings more to mind than just a memorable scene. It echoes a finding reached by a recent study conducted by the universities of Glasgow and Princeton.

The research concluded that it actually takes less than 500 milliseconds (the time it takes to say “hello”) for people to judge your character.

After playing recordings of people saying “hello,” the study’s participants were asked to rate people on a range of personality traits, including dominance, trustworthiness, attractiveness and warmth.

Surprisingly, most of the participants came to the same conclusions regarding character.

This suggests that regardless of the accuracy of our perceptions of others, the ability to quickly judge trustworthiness and attractiveness based on someone's tone of voice is a survival trait human beings have developed over time.

How People Perceive You

Nowadays, image is everything. Whether accurate or not, the way people perceive you can affect your professional career, your social life and even your intimate relationships.

This is why becoming aware of what your tone of voice is saying to other people is so crucial to your success as a public speaker.

Although we’ve heard time and again that we shouldn’t judge a book by its cover, the truth is that your audience will first judge your appearance and the tone of the voice before they really hear what you have to say. Once you’ve passed this first--albeit superficial--test of credibility, they will begin to listen to the content of your words.

Henry Wadsworth Longfellow once said that your “voice is the organ of your soul.” This is a true statement considering that your voice reflects not only what you believe about yourself, but also the attitude you have toward your audience and the content you’re presenting.

For example, you could speak in a loud, booming voice; you could mutter; you could speak quickly and not pause; or you could speak in a dry, monotone voice. Each of these would communicate something completely different to your audience, regardless of the content of your message.

Here, we detail specific characteristics of your voice and the message sent by each of them:

Volume: In general, people associate louder volumes with more powerful people .

Pitch: Both men and women prefer male and female leaders who have lower-pitched voices .They see them as more competent and dominant.

Variety: In a study of TED speakers , it was found that presenters with a higher level of vocal variety were perceived as more credible.

Speed: People are more attuned to speakers who stay within a range of 120 to 160 words per minute .

Breathing: If your audience can hear you gasping for breath because you’re speaking too quickly and taking shallow breaths, they will think you are nervous and trying too hard to make a good impression.

Clarity: Audiences are more attentive to speakers who enunciate and speak clearly. This sends the message that you are articulate, knowledgeable and competent.

Consistency: If the message you convey with your tone of voice doesn’t correspond with your facial expression and body language, then your audience will likely not find you credible.

Additionally, there are several speech habits that can seriously undermine your chances of progressing both at work and other social spheres:

Uptalk: Although popularly known as “valley girl” talk, this habit is becoming increasingly common among young men as well, especially Silicon Valley boys’ clubs . This speaking style, which tends to end phrases with a rising intonation as if they were questions, suggests a lack of confidence and maturity.

Vocal fry: Speaking below your register in a drawn out voice results in this unattractive speaking habit, which is a major turnoff for audiences in general. H ere's an example:

Problems with pitch: A voice that is too shrill or too brash come be off-putting--to the point that audiences begin to tune them out.

How to Make Others Listen to You

Speaking in a way that makes people want to listen to you starts with learning how to adjust your voice so that you’re sending the right message to your audience members.

Here are some expert tips for developing a speaking voice that keeps people’s attention, whether in a presentation given before a boardroom full of executives or a stage before thousands of people.

1 Use your diaphragm voice

One of the keys to sounding more authoritative and confident is learning to identify the kind of voice you’re using and then modify it so you’re using your diaphragm voice instead. Most people fall into one of the following categories of voice types:

Nasal voice

We’ve all heard this type of voice before, and chances are we’ve probably thought at one point in the conversation or presentation, “when is this going to end?” Although most people will keep their thoughts to themselves so as not to be rude, this kind of voice turns people off in a hurry and can really hurt your professional and social life.

Mouth voice

This type of voice (also called the head voice) is not totally repellent, but it falls short of making a lasting impression. People with this type of voice use their throat to talk. Because it creates a light, thin and grating tone, it is usually overlooked and can often be associated with someone who is underappreciated and rarely heard. When giving a presentation, this person may compensate for this by yelling, which can do more harm than good, especially to their vocal chords.

Chest voice

As the name implies, this voice comes from the chest and is generally attractive enough to keep listeners’ interest. The only problem, however, is that it isn’t the best possible speaking voice you can have.

Diaphragm voice

The optimum voice for both men and women comes from the diaphragm, which is a muscle located at the base of your lungs and moved by your abdominal muscles. This voice not only makes people want to listen to you, it also sounds natural and pleasant.

Just listen to how Margaret Thatcher, known as the Iron Lady, changed her voice over time to sound more authoritative and dominant:

2 Breathe correctly

People who don’t speak from the diaphragm also don’t breathe from the diaphragm, so in order to improve your speaking voice, you must also change the way you breathe.

Those who speak with a mouth or chest voice are usually breathing too shallowly, which gives rise to a more unnatural, nasal tone.

To change this, all you have to do is to start practicing deep breathing. Your breath must come from your abdomen--not your chest.

To make sure you’re breathing correctly, just place your fist below your last rib and see if your stomach expands and your shoulders go up and down as your breathe.

Practice breathing correctly by inhaling deeply for about 5 seconds, until you feel the air fill your stomach. Next, exhale for the same amount of time, and keep doing this until it becomes a part of your normal speech habit.

When you do this, also remember to pull your shoulders back and sit or stand up straight so that it becomes easier to breathe in deeply. This will also make you look more confident and poised.

Finally, make sure that you inhale deeply at the end of each sentence so that you can get through it without pausing to take a breath.

You can also follow the breathing exercises at the end of this TED talk given by sound consultant Julian Treasure.

3 Project from your diaphragm

When breathing from your diaphragm becomes second nature, any noise you make should come from the same place. Whether conversing, singing--or even laughing--project from your diaphragm.

4 Adjust the volume

Speak loud enough so that people at the back of the room can hear you. As mentioned earlier, people with louder voices are generally perceived as more dominant and authoritative.

5 Create emphasis

As with all types of communication, emphasis and contrast are necessary to get a point across effectively. While in writing you might need just one short sentence after a series of long sentences to create a specific effect, in speaking, you need variation in sound to make a point.

For example, read the following sentences aloud, slightly increasing the volume when pronouncing the words in bold and look at the implied meaning for each.

I didn’t tell her you were stupid. (Someone else, not me, told her this.)

I didn’t tell her you were stupid. (I most certainly didn’t tell her this.)

I didn’t tell her you were stupid. (I didn’t tell her; I implied it.)

I didn’t tell her you were stupid. (I didn’t tell her; I told someone else.)

I didn’t tell her you were stupid. (I referred to someone else, not you.)

I didn’t tell her you were stupid. (You’re still stupid.)

I didn’t tell her you were stupid . (I told her you were something else.)

This exercise, from the publication The Total Communicator illustrates why it’s so important to use the power of voice to send the right message--and not something else.

You can modify your voice to vary four important elements of sound:

Volume

Although, in general, you should raise the volume of your voice, be sure to vary it according to what you’re conveying. For instance, if you’re mentioning a side note, you would slightly lower your voice, which would act as the auditory equivalent of a parenthetical statement.

When you’re making an argument, raise your volume gradually as you build toward the point. Also, communicate a change in topic or idea by changing your volume.

Pitch

Varying your pitch requires hitting high and low notes with your voice. For example, when you ask a question, you should end your sentence on a higher note; when affirming a statement, however, you should end on a level or slightly lower note.

If used incorrectly, ending on a higher note can lead people to think that you’re insecure or that you have doubts about your statement.

Timbre

This element of sound refers to the emotional quality of your voice, as well as the attitude you convey with your words and how you say them. Not only should you choose the right words to send the right message, you should also say them in a way that expresses the attitude or emotion you want to create.

In this way, your timbre should vary in accordance with the emotional response you want to trigger in your audience. According to Julian Treasure (see TED talk above), studies show that people in general prefer voices that are “rich, smooth, warm, like hot chocolate.”

Rhythm and tempo

The first refers to the pattern created by the sounds you produce with your words; the second refers to the pace of your voice. Vary both to communicate meaning.

For example, to convey a sense of excitement or urgency, you can accelerate the pace of your voice. To draw attention to specific points, you can slow down and let your audience process what you just said.

6 Use pauses effectively

As noted here, it’s pretty rare to find a presenter who effectively uses pauses during a presentation or speech; most amateur presenters are deathly afraid of silence.

A confident and experienced presenter, however, knows how to effectively use these to drive their point home. Not only does it create suspense--expectation for what will come next--it emphasizes the point you just made by allowing your words to sink in.

Just take a look below at how Mad Men’s protagonist Don Draper commands a room with his effective use of pauses and his variation of the sound elements already mentioned.

What about your speaking voice? What does it say about your personality and attitude toward yourself and your audience? We would love to hear your reactions and thoughts in the comments section below.