Automatically detect language

Preview

This feature is subject to the "Pre-GA Offerings Terms" in the General Service Terms section of the Service Specific Terms. Pre-GA features are available "as is" and might have limited support. For more information, see the launch stage descriptions.

This page describes how to set up a recognizer to automatically recognize the language spoken in an audio file, from a preset list of potential languages.

In some situations, you don't know for certain what language your audio recordings contain. For example, if you publish your service, app, or product in a country with multiple official languages, you can potentially receive audio input from users in a variety of languages. This can make specifying a single language code for transcription requests significantly more difficult.

Multiple language recognition

Cloud Speech-to-Text offers a way for you to specify a set of languages that your audio data might contain. When creating a Recognizer or sending a recognition request, you can provide one or more languages that the audio data might include in the language_codes field. In a request with multiple languages, Cloud Speech-to-Text attempts to transcribe the audio using the best-fit language from the list of alternates you provided. Cloud Speech-to-Text then labels the transcription results with the predicted language code.

This feature is ideal for apps that need to transcribe short statements like voice commands or search. You can list up to three languages for automatic language recognition.

Caution: Though you can specify up to three languages, constrain the language list to the bare minimum needed as a best practice. The fewer language codes you specify, the higher the likelihood that Cloud Speech-to-Text successfully selects the correct one.

Note: Specifying multiple languages is only available in the Cloud Speech-to-Text global region and the us and eu multi-regions.

Note: You can only use the alternative languages feature with the long, short, and telephony models. For more information about how to specify different models, see the models documentation.

Before you begin

Sign in to your Google Cloud account. If you're new to Google Cloud, create an account to evaluate how our products perform in real-world scenarios. New customers also get $300 in free credits to run, test, and deploy workloads.

Set up a Google Cloud console project.

Set up a project

Click to:

• Create or select a project.
• Enable the Speech-to-Text API for that project.

You can view and manage these resources at any time in the Google Cloud console.

Install the Google Cloud CLI.

Note: If you installed the gcloud CLI previously, make sure you have the latest version by running gcloud components update.

To initialize the gcloud CLI, run the following command:

gcloud init

Set up a Google Cloud console project.

Set up a project

Click to:

• Create or select a project.
• Enable the Speech-to-Text API for that project.

You can view and manage these resources at any time in the Google Cloud console.

Install the Google Cloud CLI.

Note: If you installed the gcloud CLI previously, make sure you have the latest version by running gcloud components update.

To initialize the gcloud CLI, run the following command:

gcloud init

Client libraries can use Application Default Credentials to easily authenticate with Google APIs and send requests to those APIs. With Application Default Credentials, you can test your application locally and deploy it without changing the underlying code. For more information, see Authenticate for using client libraries.

1. If you're using a local shell, then create local authentication credentials for your user account:

   gcloud auth application-default login

   You don't need to do this if you're using Cloud Shell.

   If an authentication error is returned, and you are using an external identity provider (IdP), confirm that you have signed in to the gcloud CLI with your federated identity.

Also ensure you have installed the client library.

Enable language recognition in audio transcription requests

Here is an example of performing synchronous speech recognition on a local audio file with multiple languages.

Python

import os

from typing import List

from google.cloud.speech_v2 import SpeechClient
from google.cloud.speech_v2.types import cloud_speech

PROJECT_ID = os.getenv("GOOGLE_CLOUD_PROJECT")


def transcribe_multiple_languages_v2(
    audio_file: str,
    language_codes: List[str],
) -> cloud_speech.RecognizeResponse:
    """Transcribe an audio file using Google Cloud Speech-to-Text API with support for multiple languages.
    Args:
        audio_file (str): Path to the local audio file to be transcribed.
            Example: "resources/audio.wav"
        language_codes (List[str]): A list of BCP-47 language codes to be used for transcription.
            Example: ["en-US", "fr-FR"]
    Returns:
        cloud_speech.RecognizeResponse: The response from the Speech-to-Text API containing the
            transcription results.
    """
    client = SpeechClient()

    # Reads a file as bytes
    with open(audio_file, "rb") as f:
        audio_content = f.read()

    config = cloud_speech.RecognitionConfig(
        auto_decoding_config=cloud_speech.AutoDetectDecodingConfig(),
        language_codes=language_codes,
        model="latest_long",
    )

    request = cloud_speech.RecognizeRequest(
        recognizer=f"projects/{PROJECT_ID}/locations/global/recognizers/_",
        config=config,
        content=audio_content,
    )

    # Transcribes the audio into text
    response = client.recognize(request=request)
    # Prints the transcription results
    for result in response.results:
        print(f"Transcript: {result.alternatives[0].transcript}")

    return response

Clean up

To avoid incurring charges to your Google Cloud account for the resources used on this page, follow these steps.

1. Optional: Revoke the authentication credentials that you created, and delete the local credential file.

   gcloud auth application-default revoke

2. Optional: Revoke credentials from the gcloud CLI.

   gcloud auth revoke

Console

Caution: Deleting a project has the following effects:

• Everything in the project is deleted. If you used an existing project for the tasks in this document, when you delete it, you also delete any other work you've done in the project.
• Custom project IDs are lost. When you created this project, you might have created a custom project ID that you want to use in the future. To preserve the URLs that use the project ID, such as an appspot.com URL, delete selected resources inside the project instead of deleting the whole project.

If you plan to explore multiple architectures, tutorials, or quickstarts, reusing projects can help you avoid exceeding project quota limits.

In the Google Cloud console, go to the Manage resources page.

Go to Manage resources

In the project list, select the project that you want to delete, and then click Delete.

In the dialog, type the project ID, and then click Shut down to delete the project.

gcloud

Caution: Deleting a project has the following effects:

• Everything in the project is deleted. If you used an existing project for the tasks in this document, when you delete it, you also delete any other work you've done in the project.
• Custom project IDs are lost. When you created this project, you might have created a custom project ID that you want to use in the future. To preserve the URLs that use the project ID, such as an appspot.com URL, delete selected resources inside the project instead of deleting the whole project.

If you plan to explore multiple architectures, tutorials, or quickstarts, reusing projects can help you avoid exceeding project quota limits.

Delete a Google Cloud project:

gcloud projects delete PROJECT_ID

What's next

• Learn how to transcribe short audio files.
• Learn how to transcribe streaming audio.
• Learn how to transcribe long audio files.
• For best performance, accuracy, and other tips, see the best practices documentation.