Automatically detect language

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

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, Speech-to-Text attempts to transcribe the audio using the best-fit language from the list of alternates you provided. 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.

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.

In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

Go to project selector

Verify that billing is enabled for your Google Cloud project .

Enable the Speech-to-Text APIs.

Enable the APIs

Make sure that you have the following role or roles on the project: Cloud Speech Administrator

Check for the roles

1. In the Google Cloud console, go to the IAM page.

   Go to IAM
2. Select the project.

3. In the Principal column, find all rows that identify you or a group that you're included in. To learn which groups you're included in, contact your administrator.

4. For all rows that specify or include you, check the Role column to see whether the list of roles includes the required roles.

Grant the roles

1. In the Google Cloud console, go to the IAM page.

   Go to IAM
2. Select the project.
3. Click person_add Grant access .

4. In the New principals field, enter your user identifier. This is typically the email address for a Google Account.

5. In the Select a role list, select a role.
6. To grant additional roles, click add Add another role and add each additional role.
7. Click Save .

Install the Google Cloud CLI.

If you're using an external identity provider (IdP), you must first sign in to the gcloud CLI with your federated identity .

To initialize the gcloud CLI, run the following command:

gcloud  
init

In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

Go to project selector

Verify that billing is enabled for your Google Cloud project .

Enable the Speech-to-Text APIs.

Enable the APIs

Make sure that you have the following role or roles on the project: Cloud Speech Administrator

Check for the roles

1. In the Google Cloud console, go to the IAM page.

   Go to IAM
2. Select the project.

3. In the Principal column, find all rows that identify you or a group that you're included in. To learn which groups you're included in, contact your administrator.

4. For all rows that specify or include you, check the Role column to see whether the list of roles includes the required roles.

Grant the roles

1. In the Google Cloud console, go to the IAM page.

   Go to IAM
2. Select the project.
3. Click person_add Grant access .

4. In the New principals field, enter your user identifier. This is typically the email address for a Google Account.

5. In the Select a role list, select a role.
6. To grant additional roles, click add Add another role and add each additional role.
7. Click Save .

Install the Google Cloud CLI.

If you're using an external identity provider (IdP), you must first sign in to the gcloud CLI with your federated identity .

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.

  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

What's next

• Practice transcribing 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.