Text-to-Speech (speech synthesis) system development A TTS system converts text into natural speech. Modern neural TTS generate audio that is virtually indistinguishable from human speech, with a latency of 200–500 ms. The architecture and choice of engine depend on the requirements for quality, latency, and volume. ### Architectural solutions Cloud TTS — quick start, predictable quality: - OpenAI TTS: best quality in English, good in Russian - Eleven
Labs: the most natural sounding, voice cloning - Yandex SpeechKit: optimal for Russian-language products Self-hosted TTS — data control, predictable cost: - Coqui XTTS v2: multilingual, cloning in 6 seconds - Piper: lightweight, CPU-capable, good quality in Russian - Silero TTS: Russian open-source, excellent Russian
Basic system with FastAP
I
from fastapi import FastAPI
from fastapi.responses import StreamingResponse
import io
import soundfile as sf
from TTS.api import TTS
app = FastAPI()
tts = TTS("tts_models/multilingual/multi-dataset/xtts_v2")
@app.post("/synthesize")
async def synthesize(text: str, language: str = "ru"):
wav = tts.tts(
text=text,
language=language,
speaker_wav="reference_voice.wav" # для клонирования
)
buffer = io.BytesIO()
sf.write(buffer, wav, samplerate=24000, format='WAV')
buffer.seek(0)
return StreamingResponse(buffer, media_type="audio/wav")
```### Choosing an engine based on the scenario | Scenario | Recommendation | Reason | |---------|------------|--------| | Voice bot | Yandex SpeechKit / Azure | Low latency | | Audiobooks | Coqui XTTS / ElevenLabs | Maximum quality | | IVR menu | Piper / Silero | Simple phrases, low costs | | Branded voice | Fine-tuned XTTS | Uniqueness | ### Text preprocessing Before submitting to TTS, a normalizer is required: expansion of abbreviations, numbers, dates:
```python
def normalize_for_tts(text: str, language: str = "ru") -> str:
# числа: "15 000 руб." → "пятнадцать тысяч рублей"
# даты: "01.03.2024" → "первое марта две тысячи двадцать четвёртого года"
# аббревиатуры: "ООО" → "общество с ограниченной ответственностью"
...
```### Timeframe - Basic cloud TTS integration: 2-3 days - Self-hosted with queuing and caching: 1 week - Full system with custom voice: 3-4 weeks