iam passing the speed parament to elevenlabs TTS , but i did not notice any change the voice speed tts = elevenlabs.TTS(**elevenlabs_args) {'voice_id': 'bHCN6EPPyN5hYpU9UVUz', 'model': 'eleven_flash_v2_5', 'speed': 0.75} , {'voice_id': 'bHCN6EPPyN5hYpU9UVUz', 'model': 'eleven_flash_v2_5', 'speed': 1.2}

You have ot make use voice_settings parameter to pass the these settings, check the TTS clas and you will have get to know about that You can provide these aprams on voice settings

@dataclass
class VoiceSettings:
    stability: float  # [0.0 - 1.0]
    similarity_boost: float  # [0.0 - 1.0]
    style: NotGivenOr[float] = NOT_GIVEN  # [0.0 - 1.0]
    speed: NotGivenOr[float] = NOT_GIVEN  # [0.8 - 1.2]
    use_speaker_boost: NotGivenOr[bool] = NOT_GIVEN

For azure- example

elevenlabs.TTS(
                model=config.model,
                voice_id=config.voice_id,
                voice_settings=elevenlabs.VoiceSettings(
                    stability=0.5,           # Required: [0.0 - 1.0] - Controls voice consistency
                    similarity_boost=0.5,    # Required: [0.0 - 1.0] - Controls voice similarity to original
                    speed=voice_speed        # Optional: [0.8 - 1.2] - Controls speech speed
                )
            )