TTS Voice Enhancement Software for Public Speaking Training

Software solutions for teaching how to speak

There are several existing software solutions to assist people in public speaking:

  • Audio recordings use native speakers, and one strength is helping learners improve their accent. Some recordings have pauses for the learner to speak. Others are continuous so the learner speaks along with the recorded voice, similar to learning a song.
  • Some software records the learner, analyzes the pronunciation, and gives feedback.
  • Speech synthesis or text to speech (TTS) sites and software let learners hear pronunciation of arbitrary written text, with pronunciation similar to a native speaker.


Drawbacks of currently available TTS voices

The third  solution, TTS, is potentially a very powerful tool. However currently available TTS voices have limitations in accuracy and comprehensibility and as a result seem robotic:

At the individual word and simple sentence level (segmental), TTS is perceived to be as good as native voices.  However, when speaking phrases and clauses in compound or complex sentences (suprasegmental) TTS is seen as unnatural and lacking native rhythm in phrasal stress, intonation and pauses.

Inaccuracy in speaking phrases and clauses makes TTS harder to understand when compared to the human voice.


TTS Voice Enhancement Software

Tuval's TTS voice enhancement software removes the restrictions on currently available TTS voices and enables the TTS voice to read clauses and phrases in compound or complex sentences naturally with correct intonation and pauses - without sounding robotic.  Listeners can better process the TTS speaker's information - making the material easier to understand and retain.

Enhanced TTS voices are easier to listen to and understand even for long periods of time, and so can be used successfully in applications that require longer speech, such as e-learning, presentations and audio books.

The TTS voice enhancement software helps at any rate of speaking. It allows a TTS voice both to speak fast and still be well-understood and to speak slowly and clearly without being boring and difficult to listen to.

Application to Public Speaking

The software also addresses a potentially large market of English speakers that need to speak in public for any reason: business, civic, family. The speaker inputs the text of his speech and the enhanced TTS voice will read it back with the correct pauses and accents at any desired speed.

To learn how to present the speech, the speaker starts by imitating the TTS voice at slow speed and then gradually increases the speed until he can present at fast speed.

The software can also produce a marked-up text copy showing where to place pauses and accents..


The sections below illustrate Tuval's TTS voice enhancement software:

1. Comparing clips of enhanced TTS voices at slow-medium-fast speeds reading the text of "Rachel's English - Multi-Syllable Words".

2. Comparing clips of enhanced TTS voices at slow-medium-fast speeds reading the text of "Andy's speeches".

The learner would begin by imitating the slow clip, advance to the medium clip and then to the fast clip.

Two TTS voices are used: male voice Ryan and female voice Sharon - both from Acapela-Group

The source text appears on the right, where pauses are marked by vertical bar separators (|).

Enhanced TTS voice at various speeds. Multi-syllable

Sample From Rachel's English - Multi-Syllable Words

Source: Multi-syllable words  

◊ Enhanced TTS Voice at Various Speeds. Comparison with Real Voice

Real Voice: English Instructor Rachel

TTS Voice: Acapela Sharon

  ◊ Enhanced TTS Voice at Various Speeds. Comparison with Real Voice

Real Voice: Voice Coach Andy Krieger

TTS Voice: Acapela Ryan

source text

Source -

Multi-syllable words| can be really tricky. There are so many sounds| and transitions in them. So today| we’re going to talk-about | how to work∣ on multi-syllable words.¶

I encourage you| to keep a running list| of long words |that have come-up in conversation for you| that are hard| for you to say. Maybe| they are words| that relate to your field of study | or work.¶

Let’s use as an example∣ the word "underestimait". First, look it up in the dictionary| and get the I P A.. But what I really want to talk about today| is, make sure| you know∣ which syllables| are stressed.¶

This is a five syllable word| with stress| on the middle syllable. There is∣ secondary stress∣ in this word| marked∣ by the little line| at the bottom. I’m going to say, don’t worry about that. They’re more like∣ unstressed∣ syllables |than∣ stressed ∣syllables. ¶

Let’s start ∣by practicing∣ the stressed∣ syllable. Do you know the shape| of a stressed syllable ? I made a video| a long time ago| about how the voice should curve up |and then down |in a stressed syllable. The sounds| are the most important | in this stressed syllable — they should be the clearest |in your word. Practice| just the stressed syllable |using | a hand movement. The shape| really is important| in making the word sound natural.¶

Now| let’s look∣ at the rest| of the syllables. We have two before| and two after. Practice | these syllables| together. There’s no need| to practice them separately| like the stressed syllable.¶

At the beginning| of the video, I talked-about| how long words| can be hard | because there are so many sounds. But I want you to see that ∣ in unstressed syllables∣ the sounds∣ don’t have to be fully formed |and fully pronounced. These sounds| are quieter, flatter in pitch, faster, simpler. This | should make long words easier, but that doesn’t mean you don’t have to practice them. You do, you need to repeat a new word |over| and over, but the point is to break it up| into simplified |and stressed| syllables.¶

Put together a list| of long words |and work through them |this way. I really think | that breaking up a word| into stressed| and unstressed| syllables |is the best way to master it — along with repetition. The more |you get used| to the contrast| of stressed |and unstressed| syllables, the better. Stress | really matters |in American English.¶    

Enhanced TTS voice at various speeds. Andy speeches

Andy\'s Speeches

◊ Enhanced TTS Voice at Various Speeds.

TTS Voice: Acapela Sharon


◊ Enhanced TTS Voice at Various Speeds.

TTS Voice: Acapela Ryan

source text

Bees | are a very useful insect. They spread pollen| from flower to flower. Many crops |depend on bees| for fertilization. Bees| also produce honey that people use for food.  ¶

Mozart |was a composer of music. He is one| of the most famous of all. His music| is still listened to |by millions of people |all over the world, especially his operas, such as The Magic Flute, Don Giovanni, and The Marriage of Figaro. He had| a very difficult life, but his music |makes people happy. Mozart| lived| in what is today Austria, from 1756 to 1791. When he was about 7, he wrote| his first opera |and symphony.   ¶

Dinosaurs| lived | on the earth |many millions| of years ago. They lived| on the earth| for 165  million years, but mysteriously disappeared| about 65 million years ago.   Some kinds of dinosaurs| were: Stegosaurus, Tyranosaurus Rex, Allasourus, Tryserotops, and others. There are many theories | as to why they disappeared. Perhaps a comet| hit the earth |and the climate changed, making the earth too hot| for the large creatures to survive. Or| a volcano exploded. We can see |the bones of dinosaurs| in many museums |all over the world| today.¶

Canada| is one| of the largest countries | in the world – in area. But| it only has | about 33 million people. We have 12 provinces| such as: B.C., Ontario, and Quebec. Our main cities| are Montreal, Toronto and Vancouver. Our country| exports| oil, lumber, wheat, and minerals| such as gold, nickel, and copper| to other countries |all over the world. Our Prime Minister| is Justin Trudeau.¶

I have | a wonderful job. I work| as a flight attendant| for Air Canada. I love flying. I enjoy | taking care of | the passengers |and helping to make| their traveling enjoyable. Many| of the other flight attendants |have become my friends. When we arrive | in a city| we stay| at the finest hotels. Over the years| I have seen many| of the great cities| of the world. For that reason alone, I highly recommend| this job to you. Work hard in school. Get a good education and, maybe, one day, you will enjoy working| as a flight attendant| as much as I ∣have.