Text-to-Speech App using gTTS and Streamlit

Introduction

Text-to-Speech (TTS) technology has become a core part of modern applications — from accessibility tools and language learning platforms to podcast generators and voice assistants. Thanks to Python’s gTTS (Google Text-to-Speech) library, you can convert any text into natural-sounding audio in over 30 languages with just a few lines of code.

In this tutorial you will build a polished TTS web app using gTTS and Streamlit. The finished app will let users type or paste any text, choose a language and speech speed, preview the audio directly in the browser, and download the generated MP3 file.

This project pairs naturally with our Translator App — you can translate text first, then feed the translation into this TTS app to hear it spoken aloud. It is also a core module of the larger SANGAM AI toolkit.

🎬 Watch the Full Video Tutorial:
Watch the walkthrough on YouTube: Building a Simple Text-to-Speech Converter with Python and Streamlit

What is gTTS?

gTTS (Google Text-to-Speech) is a Python library that interfaces with Google Translate’s TTS API. It sends your text to Google’s servers and returns an MP3 audio stream, which you can then save or play back.

gTTS vs Other TTS Libraries

gTTS is the perfect choice for beginners and small projects: it is completely free, requires zero API key setup, and produces Google’s polished TTS voices.

Prerequisites

Make sure you have the following installed before starting:

• Python 3.8+ — Download from python.org.
• Libraries — Install with pip:

pip install streamlit gTTS

Supported Languages

gTTS supports over 30 languages and regional variants. Here is a selection of the most commonly used ones:

For the full list, visit the gTTS documentation.

Project Structure

tts_app/
├── tts_app.py          ← Main Streamlit application
└── requirements.txt    ← pip dependencies

Create requirements.txt:

streamlit
gTTS

Step 1: Create the Basic App

Create tts_app.py and set up the page:

import streamlit as st
from gtts import gTTS, lang
import io

st.set_page_config(
    page_title="Text to Speech",
    page_icon="🔊",
    layout="centered"
)

st.title("🔊 Text-to-Speech Converter")
st.write(
    "Convert any text into natural-sounding speech. "
    "Choose your language, adjust the speed, then preview or download the audio."
)

Step 2: Build the Language Selector

gTTS provides a helper function lang.tts_langs() that returns a dictionary of all supported language codes and their names. We can use this to build a dynamic dropdown:

# Get all supported languages from gTTS
all_langs = lang.tts_langs()  # Returns {"en": "English", "hi": "Hindi", ...}

# Flip to {name: code} for display
lang_name_to_code = {v: k for k, v in all_langs.items()}
lang_names = sorted(lang_name_to_code.keys())

col1, col2 = st.columns(2)

with col1:
    selected_lang_name = st.selectbox(
        "🌍 Language",
        lang_names,
        index=lang_names.index("English"),
    )
    lang_code = lang_name_to_code[selected_lang_name]

with col2:
    slow_mode = st.radio(
        "🐢 Speech Speed",
        options=["Normal", "Slow"],
        horizontal=True,
    )
    is_slow = slow_mode == "Slow"

Step 3: Text Input Area

Add a large text area where users can type or paste any content:

st.divider()

text_input = st.text_area(
    "📝 Enter your text:",
    height=220,
    placeholder=(
        "Type or paste your text here...\n\n"
        "Examples:\n"
        "• A paragraph you want to hear read aloud\n"
        "• A script for a video or podcast\n"
        "• A translated phrase you want to pronounce correctly"
    ),
    max_chars=5000,
)

char_count = len(text_input)
st.caption(f"{char_count} / 5,000 characters used")

The 5,000 character limit prevents accidental very large requests to Google’s TTS API.

Step 4: Generate and Play the Audio

This is the core of the app — converting text to speech and playing it in the browser:

if st.button("🎙️ Convert to Speech", type="primary", use_container_width=True):
    if not text_input.strip():
        st.warning("Please enter some text before converting.")
    else:
        with st.spinner("Generating audio..."):
            try:
                # Generate TTS audio
                tts = gTTS(text=text_input, lang=lang_code, slow=is_slow)

                # Write to an in-memory byte buffer (no temp files needed)
                audio_buffer = io.BytesIO()
                tts.write_to_fp(audio_buffer)
                audio_buffer.seek(0)

                st.success(f"✅ Audio generated in {selected_lang_name}!")

                # Display the inline player
                st.audio(audio_buffer, format="audio/mp3")

                # Download button
                audio_buffer.seek(0)
                st.download_button(
                    label="⬇️ Download MP3",
                    data=audio_buffer,
                    file_name="speech.mp3",
                    mime="audio/mpeg",
                    use_container_width=True,
                )

            except Exception as e:
                st.error(f"Something went wrong: {e}")
                st.info(
                    "Tip: Check your internet connection — "
                    "gTTS requires access to Google's servers."
                )

Using io.BytesIO() instead of saving to a file on disk is the correct pattern for Streamlit: it keeps everything in memory and works perfectly in cloud environments where writing to disk is restricted.

Step 5: Add Multi-Language Demo

Let us add a helpful demo section that converts a greeting phrase into multiple languages at once — great for showcasing the app’s capabilities:

st.divider()
with st.expander("🌐 Multi-Language Demo — Hear 'Hello' in 6 languages"):
    demo_phrases = {
        "English": ("en",  "Hello! Welcome to the Text-to-Speech app."),
        "Hindi":   ("hi",  "नमस्ते! टेक्स्ट-टू-स्पीच ऐप में आपका स्वागत है।"),
        "Spanish": ("es",  "¡Hola! Bienvenido a la aplicación de texto a voz."),
        "French":  ("fr",  "Bonjour! Bienvenue dans l'application de synthèse vocale."),
        "German":  ("de",  "Hallo! Willkommen bei der Text-to-Speech-App."),
        "Japanese":("ja",  "こんにちは！テキスト読み上げアプリへようこそ。"),
    }

    for language, (code, phrase) in demo_phrases.items():
        col_a, col_b = st.columns([1, 3])
        with col_a:
            st.write(f"**{language}**")
        with col_b:
            if st.button(f"▶️ Play", key=f"demo_{code}"):
                tts = gTTS(text=phrase, lang=code, slow=False)
                buf = io.BytesIO()
                tts.write_to_fp(buf)
                buf.seek(0)
                st.audio(buf, format="audio/mp3")

Complete tts_app.py

Here is the complete, final version of the app:

import streamlit as st
from gtts import gTTS, lang
import io

st.set_page_config(page_title="Text to Speech", page_icon="🔊", layout="centered")
st.title("🔊 Text-to-Speech Converter")
st.write("Convert text to natural speech in 30+ languages. Preview and download the audio.")

all_langs = lang.tts_langs()
lang_name_to_code = {v: k for k, v in all_langs.items()}
lang_names = sorted(lang_name_to_code.keys())

col1, col2 = st.columns(2)
with col1:
    selected_lang_name = st.selectbox("🌍 Language", lang_names, index=lang_names.index("English"))
    lang_code = lang_name_to_code[selected_lang_name]
with col2:
    is_slow = st.radio("🐢 Speed", ["Normal", "Slow"], horizontal=True) == "Slow"

st.divider()
text_input = st.text_area("📝 Enter your text:", height=220, max_chars=5000,
                           placeholder="Type or paste your text here...")
st.caption(f"{len(text_input)} / 5,000 characters")

if st.button("🎙️ Convert to Speech", type="primary", use_container_width=True):
    if not text_input.strip():
        st.warning("Please enter some text.")
    else:
        with st.spinner("Generating audio..."):
            try:
                tts = gTTS(text=text_input, lang=lang_code, slow=is_slow)
                buf = io.BytesIO()
                tts.write_to_fp(buf)
                buf.seek(0)
                st.success(f"✅ Ready in {selected_lang_name}!")
                st.audio(buf, format="audio/mp3")
                buf.seek(0)
                st.download_button("⬇️ Download MP3", buf, "speech.mp3", "audio/mpeg",
                                   use_container_width=True)
            except Exception as e:
                st.error(f"Error: {e}")

st.divider()
with st.expander("🌐 Multi-Language Demo"):
    demos = {"English": ("en", "Hello! Welcome."), "Hindi": ("hi", "नमस्ते!"),
             "Spanish": ("es", "¡Hola!"), "French": ("fr", "Bonjour!")}
    for name, (code, phrase) in demos.items():
        c1, c2 = st.columns([1, 3])
        c1.write(f"**{name}**")
        with c2:
            if st.button("▶️ Play", key=f"d_{code}"):
                t = gTTS(phrase, lang=code)
                b = io.BytesIO()
                t.write_to_fp(b)
                b.seek(0)
                st.audio(b, format="audio/mp3")

Run the App

streamlit run tts_app.py

How gTTS Works Internally

Under the hood, gTTS:

1. Splits your text into chunks of ~100 characters (Google’s TTS API has a per-chunk limit).
2. Sends each chunk as a GET request to https://translate.google.com/translate_tts.
3. Concatenates the MP3 chunks into a single audio stream.
4. Returns the combined stream, which you write to a file or BytesIO buffer.

This is why a working internet connection is required — gTTS is not an offline library.

Common Use Cases

Troubleshooting

Extending the App

Batch File Conversion

You can extend the app to convert an uploaded .txt file into speech:

uploaded = st.file_uploader("Upload a .txt file", type=["txt"])
if uploaded:
    file_text = uploaded.read().decode("utf-8")
    st.text_area("File Preview", file_text[:500] + "...", disabled=True)
    if st.button("Convert File to Speech"):
        tts = gTTS(text=file_text[:5000], lang=lang_code, slow=is_slow)
        buf = io.BytesIO()
        tts.write_to_fp(buf)
        buf.seek(0)
        st.audio(buf, format="audio/mp3")

Speaking Numbers and Abbreviations

gTTS reads numbers as digits by default. To have it read 2025 as “twenty twenty-five” instead of “two thousand and twenty-five”, convert it first:

import inflect
p = inflect.engine()
number_as_words = p.number_to_words(2025)  # → "two thousand and twenty-five"

Install inflect with pip install inflect.

Related Projects on This Blog

• Translator App — Translate text first, then paste it into this TTS app to hear the pronunciation.
• SANGAM AI Toolkit — The TTS module in SANGAM AI is built on the same gTTS foundation shown here.
• Chatbot with Mistral AI — Combine the chatbot with this TTS app so the AI speaks its responses aloud.

Conclusion

You have built a production-ready Text-to-Speech web app using Python, gTTS, and Streamlit. The app handles text input, language selection, speed control, in-browser audio playback, and MP3 downloads — all in under 50 lines of core logic.

TTS is a remarkably versatile tool. Whether you are building a language-learning assistant, an accessibility aid, or a voice-over generator for your content, the techniques in this tutorial give you a solid, extensible foundation.

Resources:

• gTTS Documentation
• gTTS on PyPI
• Streamlit Audio API
• Streamlit Download Button
• Google Text-to-Speech Overview