SILMA Text-to-Speech

Overview

SilmaTTSService provides low-latency real-time text-to-speech Pipecat integration via a WebSocket API. It streams audio from SILMA TTS over a WebSocket you can play through any Pipecat transport. SILMA selects the language by model rather than by a language parameter:

silma-tts-v2-english — English
silma-tts-v2-msa — Modern Standard Arabic
silma-tts-v2-ksa — Arabic in the Saudi (Najdi) dialect

For an updated list of languages, please visit SILMA AI Products Pick a preset voice, or a voice you have cloned in your SILMA account.

Source Repository

Package source, the foundational example, and issue tracker

PyPI Package

The pipecat-silma package on PyPI

SILMA AI

Product overview, voices, and the TTS playground

API Keys

Create and manage your SILMA API keys

Installation

Install the community package. It is published separately from pipecat-ai:

uv add pipecat-silma

Prerequisites

Account and API key

Create an account at SILMA App
Copy an API key from API Keys

Set it in the environment:

export SILMA_API_KEY="..."

Configuration

str

default:"None"

SILMA API key. If omitted, the service reads SILMA_API_KEY.

SilmaTTSService.Settings

default:"None"

Model, voice, and prosody. See Settings. Every field is also available as a direct constructor argument.

str

default:"https://api.silma.ai/tts/v2"

Override this only for a non-production SILMA endpoint. The WebSocket URL is derived from it, so http:// becomes ws:// for a local mock server.

float

default:"20.0"

How often to ping an idle connection, in seconds. It has to stay comfortably inside the read timeout of whatever proxy fronts the API — lower it if yours is shorter than the default assumes. Getting it wrong is not fatal: the next utterance reopens the socket, at the cost of a reconnect on its first word.

int

default:"None"

SILMA renders 24 kHz audio and takes no sample-rate parameter, so the service pins its rate at 24000. Leave this unset; passing anything other than 24000 raises ValueError rather than mislabelling the audio. Let the output transport resample if it needs a different rate.

Settings

Pass these through SilmaTTSService.Settings(...). They can also be updated while the pipeline is running, with TTSUpdateSettingsFrame.

Parameter	Type	Default	Description
`model`	`str`	`"silma-tts-v2-msa"`	Model id, which also selects the language.
`voice`	`str`	`"sarah"`	Preset voice id. See the table below.
`language`	`Language`	`None`	Convenience: sets `model` to the one that speaks it. `EN`, `AR`, and `AR_SA` are mapped.
`creativity`	`float`	`None`	Variance in speech prosody 0-1. Left to SILMA’s default when unset.
`speed`	`float`	`None`	Speaking rate 0-1. Left to SILMA’s default when unset.
`user_id`	`str`	`None`	Your SILMA user id. Required for cloned voices and pronunciation overrides.
`custom_audio_id`	`str`	`None`	Cloned voice id, e.g. `voice_1769817467123`. Requires `user_id`.
`enable_server_pronunciation_overrides`	`bool`	`False`	Apply the pronunciation overrides configured on your account. Requires `user_id`.

creativity and speed are omitted from the request entirely unless you set them, so SILMA’s own defaults apply.

Models and voices

Model	Language	Voices
`silma-tts-v2-english`	English	`james`, `emma`
`silma-tts-v2-msa`	Modern Standard Arabic	`sarah`, `salma`, `salwa`, `saja`, `sultan`, `salman`, `sulaiman`, `salim`
`silma-tts-v2-ksa`	Arabic, Saudi (Najdi) dialect	same as MSA

Voice catalogs and model coverage can change. See app.silma.ai or API specification for the current list.

Usage

import os

from pipecat.pipeline.pipeline import Pipeline
from pipecat.pipeline.worker import PipelineParams, PipelineWorker
from pipecat_silma import SilmaTTSService

tts = SilmaTTSService(
    api_key=os.getenv("SILMA_API_KEY"),
    settings=SilmaTTSService.Settings(
        model="silma-tts-v2-msa",
        voice="sarah",
    ),
)

pipeline = Pipeline(
    [
        transport.input(),
        stt,
        user_aggregator,
        llm,
        tts,
        transport.output(),
        assistant_aggregator,
    ]
)

worker = PipelineWorker(
    pipeline,
    params=PipelineParams(enable_metrics=True, enable_usage_metrics=True),
)

To speak English instead of Arabic, change the model and pick an English voice:

tts = SilmaTTSService(
    settings=SilmaTTSService.Settings(
        model="silma-tts-v2-english",
        voice="emma",
    ),
)

Pronunciation hints

SILMA reads phone numbers, email addresses and links correctly when they are tagged in the text:

You can reach us on <STAG_PN>92005455</STAG_PN> or at <STAG_EMAIL>hi@silma.ai</STAG_EMAIL>.

The API caps a request at 250 characters, so the service splits longer text on word boundaries and sends it as sequential requests over the same socket. The splitter keeps these tags intact, so a tag is never cut in half across two requests. Instruct your LLM to emit them — the foundational example shows how. Account-level pronunciation overrides configured at app.silma.ai/control apply when you pass both user_id and enable_server_pronunciation_overrides=True.

Cloned voices

Upload a voice under Custom Voices at app.silma.ai/voices, then pass its id together with your user id:

tts = SilmaTTSService(
    settings=SilmaTTSService.Settings(
        model="silma-tts-v2-ksa",
        voice="sarah",
        user_id="...",
        custom_audio_id="voice_1769817467123",
    ),
)

A cloned voice overrides the preset, so the voice you pair it with does not matter.

Interruptions

SilmaTTSService extends InterruptibleTTSService. SILMA’s protocol has no cancel message, so speech is stopped by dropping the socket and reconnecting — which the service does without blocking the frame that clears buffered audio, so a barge-in takes effect immediately rather than after the teardown completes.

Compatibility

Tested with Pipecat 1.8.1 (pipecat-ai>=1.8.1), on Python 3.11 and later.

Get Started

Pipecat Server

Client SDKs

Pipecat Flows

Pipecat Cloud

CLI

Pipecat Context Hub

SILMA Text-to-Speech

Overview

Source Repository

PyPI Package

SILMA AI

API Keys

Installation

Prerequisites

Account and API key

Configuration

Settings

Models and voices

Usage

Pronunciation hints

Cloned voices

Interruptions

Compatibility

​Overview

Source Repository

PyPI Package

SILMA AI

API Keys

​Installation

​Prerequisites

​Account and API key

​Configuration

​Settings

​Models and voices

​Usage

​Pronunciation hints

​Cloned voices

​Interruptions

​Compatibility

Overview

Installation

Prerequisites

Account and API key

Configuration

Settings

Models and voices

Usage

Pronunciation hints

Cloned voices

Interruptions

Compatibility