Synthetic Media - Speech Synthesis

Speech synthesis refers artificial production of human speech using modern technology. This involves conversion of text to speech or cloning someone voice. Speech synthesis is commonly used in virtual assistants, audiobooks, and accessibility tools. In this section, we will explore different techniques in speech synthesis, text-to-speech algorithms, and examples of their applications.

Techniques in Speech Synthesis

There are different methods used to create synthetic speech. Below are the types of techniques commonly used in speech synthesis:

• Text-to-Speech (TTS): This method converts written text into spoken words, allowing computers to read text aloud.
• Voice Cloning: This technique makes a computer sound like a specific person by learning their voice from recordings.
• Concatenative Synthesis: This technique uses small pieces of recorded speech, like sounds or words, and puts them together to form sentences.

Text-to-Speech (TTS) Algorithm

A Text-to-Speech (TTS) system converts written text into spoken words using a combination of natural language processing, phonetic analysis, and audio synthesis techniques. Below are the key steps in the TTS algorithm:

• Text Preprocessing: Tokenizes and normalizes input text, handling abbreviations, numbers, and special characters to prepare for speech conversion.
• Linguistic Processing: Performs natural language processing (NLP) to understand syntax, grammar, rhythm and stress patterns.
• Phonetic Conversion: Converts text into phonemes, the basic units of sound in speech, to map how words are pronounced.
• Speech Synthesis: Generates speech using methods like concatenative synthesis, parametric synthesis, or neural-based approaches (e.g., Tacotron and WaveNet).
• Audio Output: Converts the generated phonetic data into audio that can be played back as natural speech.

Applications of Speech Synthesis

• Virtual Assistants: Speech synthesis are used in virtual assistants like Siri, Google Assistant, and Alexa.
• Accessibility: TTS systems make digital content more accessible by helping visually impaired users by converting written content into spoken words.
• Audiobooks: AI-generated voices are used in audiobooks which are converted from human written text to audio using text-to-speech devices.
• Customer Service: Automated customer service systems use synthetic speech to interact with customers in real time, improving response time and reducing human labor costs.

AI Speech Generation Tools

Several AI tools are available for generating synthetic speech. Some popular ones include:

• Google WaveNet: A TTS system developed by Google that generates realistic human speech from text inputs.
• Lyrebird: A tool for voice cloning that can replicate a person's voice using just a few minutes of recorded audio.
• Amazon Polly: A cloud-based service that turns text into lifelike speech, used in applications like virtual assistants and interactive voice response systems.
• IBM Watson Text-to-Speech: A TTS service that converts written text into natural-sounding speech using advanced neural models.