What is a Text-to-Voice Generator?
What is a Text-to-Voice Generator?
A text-to-voice generator is software that uses artificial intelligence (AI) technologies to convert digital text into an audio file. The user interface in modern applications is moving beyond touch to voice interactions, with customers asking the app to do tasks and the app responding verbally. A text-to-voice generator allows app developers to automatically add voice capabilities to applications using existing text content. It comes with built-in high-quality voices that can generate audio files mimicking dozens of authentic human voices, accents, and dialects.
What are the use cases of a text-to-voice generator?
There are several business use cases of a text-to-voice generator.
Generate speech in multiple languages
Text-to-voice generators allow organizations to quickly create audio files of the same text in different languages. For businesses with a global audience, this flexibility helps support a multilingual customer base.
Engage customers with a natural-sounding speech
A text-to-voice tool lets you create natural and realistic-sounding voices for your customer service lines. Instead of robotic audio, a natural-sounding voice puts customers at ease and helps them navigate interactive customer support systems seamlessly.
Create cost-effective audio files for media
Whether creating audio files for video games, animations, or other forms of media, a text-to-speech generator is a fast and cost-effective way to bring text to life. Businesses can use SSML, an XML-based markup language, to intuitively modify the emphasis, phrasing, or intonation of audio files.
Support differently abled learners
Another use of text-to-speech generator software is to help students who struggle with dyslexia, other learning difficulties, or visual impairment. By transforming any text into spoken word, educators can make their learning resources more accessible. For students with learning difficulties or any visual impairment, this supportive software streamlines the learning experience.
How does a text-to-voice generator work?
Transforming text with TTS is a multi-step process that relies on linguistic analysis, speech synthesis, and artificial intelligence models. The AI model is trained on a large audio dataset with corresponding transcriptions in the target language. Depending on the model architecture, different text-to-voice approaches are available.
Concatenative synthesis
This method creates speech by combining small segments of recorded human speech. The AI model analyzes its training audio data to identify the phonemes (individual sounds), diphones (sound transitions from the middle of one phoneme to the middle of the next), and syllables or words. It maps these components to individual written words.
When you input text, the system:
- Converts the text into phonetic representations.
- Chooses the best-matching audio segments to cover the sequence of sounds.
- Concatenates or combines the individual components to form complete utterances corresponding to the input text.
It prioritizes smooth transitions and natural prosody (intonation, rhythm, stress) during the concatenation process.
Neural text-to-speech synthesis
Neural text-to-speech (NTTS) is a further advancement on concatenative synthesis. It has two main components.
Sequence to spectrogram model
This is a sequence-to-sequence model that transforms text phoneme sequences into sound wave sequences. It generates a spectrogram, a visual representation of how sound energy is distributed across different frequencies over time. It captures the flow and context within the sequence, emphasizing acoustic features that make voices sound natural to the human ear, like stress, pitch, rhythm, and intonation.
Neural vocoder
Once the spectrogram is generated, the output is passed to a neural vocoder — a specialized deep learning model that converts spectrograms into an actual audio waveform. It produces high-resolution, continuous speech that is smoother, clearer, and more realistic-sounding than what concatenative synthesis could achieve.
Generative text-to-speech
Generative text-to-speech uses billion-parameter large language models to produce speech that is emotionally expressive, context-aware, and conversational. It can learn on the go, adapting speaking style to the content and simulating persuasive, empathetic, or excited tones as the conversation proceeds. It represents a shift from text-to-voice to text-to-meaningful-voice, so AI-generated voices sound very similar to real human voices.
The two-stage process in generative TTS works as follows:
Text-to-speech code conversion
A transformer component converts raw input text into intermediate speech codes. Speech codes are compact, learned representations of data that encode prosody (rhythm, stress, intonation), emotion, and linguistic nuance. It can interpret the semantics and intent of the text, understanding tone, emphasis, and even emotional cues.
Speech code-to-waveform decoder
The speech codes are then passed to a convolutional decoder, which transforms them into raw audio waveforms. This decoder works incrementally, meaning it can stream speech in real-time. It ensures low latency and delivers smooth, high-fidelity audio output for a realistic AI voice.
How can you implement a text-to-voice generator?
Modern text-to-speech generators don’t require you to train models from scratch. You can use a pre-built text-to-voice generator as a fully managed cloud service via APIs. Here is the process to follow when implementing a text-to-voice generator:
Input your text
Upload the full text that you want to transform into an audio file. You can either upload a plaintext or use the SSML format. The latter option is preferable, as SSML allows you to control aspects such as pitch, volume, speech rate, and pronunciation.
Select an available voice
Browse the available portfolio of languages and accents (male and female options available) to find a voice that you want to read your text. Select this voice ID when launching the speech synthesis task.
Generate audio output
Receive your audio file in the format that suits you. You can stream real-time audio or store the generated audio in a file format for later consumption.
What capabilities should you look for when choosing a text-to-voice generator?
There are several core capabilities and characteristics to look for when selecting an effective text-to-voice generator.
Ease of use
The text-to-voice generator should provide flexible APIs and SDKs for easy integration with application code. It should support standardized technology like Speech Synthesis Markup Language (SSML), so developers can add tags for emphasis, intonation, and phrasing to the input text. This gives improved voice control while making the audio more realistic and natural.
High customizability
The text-to-voice generator should support numerous languages, accents, and language variants. Organizations may have distinct vocabularies due to the industry or region in which they operate. The text-to-voice generator should allow customization of pronunciations in the generated audio. It should also allow you to adapt the maximum time that a particular phrase runs for. Adjusting these parameters gives businesses the option to customize the sound of their text-to-speech voices in ways that best suit their use case.
Optimization options
A text-to-speech generator should support various sampling rates, allowing businesses to optimize audio quality while honing bandwidth usage. Changing the sampling rate will alter the MP3, OGG, and PCM sizes of a file.
Integrations with other tools
If you want to use text-to-speech software in tandem with customer support systems, then the ability to integrate into contact center tools is mandatory. Your text-to-voice generator software should integrate with other customer-facing tools to streamline customer experience management.
How can AWS support your text-to-voice generator requirements?
Amazon Polly is a fully managed AI voice generator service — you simply send your text file to the Amazon Polly API, and it returns the audio stream immediately. You can store the audio stream in a standard audio file format or play it directly.
With Amazon Polly, you can:
- Convert text to speech in dozens of lifelike voices and languages, supporting all types of users.
- Adjust the speech rate, pitch, or volume in the output as needed.
- Cache and replay generated speech at no additional cost.
- Implement real-time text-to-speech capabilities at high speed and on a large scale.
You can also work with the Amazon Polly team to create a synthetic voice for your organization's exclusive use, differentiating your brand with a unique vocal identity. Here is an example demo of the Amazon Polly voice, Matthew.
Get started with the AWS text-to-voice generator by creating a free account today.