What is Text-to-Speech (TTS) Technology and How Does It Work?

With the advancement of technology, our communication with devices has moved from being purely visual to a vocal dimension. One of the most important actors in this transformation is Text-to-Speech (TTS) technology.

So, how do TTS systems read written text in a human-like voice, in which areas are they used, and what awaits us in the future?

1. What is Text-to-Speech (TTS)?

Text-to-Speech (TTS) is an assistive technology that converts written text in digital environments into spoken voice using artificial speech synthesis methods. While initially sounding robotic and mechanical, today these voices have reached a level almost indistinguishable from real human speech, thanks to artificial intelligence and deep learning models.

2. How Does TTS Technology Work?

A modern TTS system basically consists of two main stages:

Text Analysis (Preprocessing)

The system first analyzes the written text. During this stage, abbreviations are expanded, numbers are written out, and sentence boundaries are determined based on punctuation marks. Furthermore, the emphasis and correct pronunciation of words (phonetic analysis) based on their roles in the sentence are identified.

Speech Synthesis (Generation)

After the text is phonetically parsed, it's time to generate the sound waves:

• Older Method (Concatenative Synthesis): Worked by joining together thousands of pre-recorded syllables or word fragments. The voices sounded robotic and choppy.
• Modern Method (Neural Networks and Deep Learning): Deep learning algorithms, like WaveNet, mimic the frequency features of human voices to generate smooth and natural sound waves completely from scratch. The pauses, intonation, and emphasis in speech are adjusted by AI at this stage.

3. Common Use Cases

Text-to-speech technology is actively used in many fields today:

• Accessibility: Screen readers and audiobooks play a vital role for visually impaired individuals or those with reading difficulties.
• Education: For language learners, hearing the correct pronunciation of words accelerates the learning process.
• Smart Assistants: Systems like Siri, Google Assistant, and Alexa communicate with users vocally using this technology.
• Content Creation: Creating audio versions of articles (podcast format) or using AI voiceovers in video content is becoming increasingly popular.

The Future

In the future, TTS systems will not only read the text but will also be able to analyze the emotional state (sadness, joy, excitement) contained in the text and adjust the intonation accordingly. Today, you can read aloud and download any text in seconds using practical browser-based tools.