Detecting languages (Advanced)

This document describes how to use the Cloud Translation - Advanced to detect the language of a string.

Note: See Migrating to Translation Advanced for details regarding differences between Basic and Advanced.

Before you begin

Before you can start using the Cloud Translation API, you must have a project that has the Cloud Translation API enabled, and you must have a private key with the appropriate credentials. You can also install client libraries for common programming languages to help you make calls to the API. For more information, see the Setup page.

Detecting the language of a text string

You can detect the language of a text string by sending an HTTP request using a URL of the following format:

https://translation.googleapis.com/v3/projects/PROJECT_NUMBER_OR_ID/locations/global:detectLanguage

Note: project-id works as well, but project-number is preferred going forward.

Detecting the language of a single string

REST & CMD LINE

To detect the language of some text, make a POST request and provide the appropriate request body. The following shows an example of a POST request using curl and PowerShell. The example uses the access token for a service account set up for the project using the Google Cloud Google Cloud CLI. For instructions on installing the Google Cloud CLI, setting up a project with a service account, and obtaining an access token, see the Setup page.

Before using any of the request data, make the following replacements:

• PROJECT_NUMBER_OR_ID: your Google Cloud project number or ID

HTTP method and URL:

POST https://translation.googleapis.com/v3/projects/PROJECT_NUMBER_OR_ID/locations/global:detectLanguage

Request JSON body:

{
   "content":"Доктор Ватсон, иди сюда!"
}

To send your request, choose one of these options:

curl

Note: Ensure you have set the GOOGLE_APPLICATION_CREDENTIALS environment variable to the path for your service account private key file.

Save the request body in a file called request.json, and execute the following command:

curl -X POST \
-H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
-H "Content-Type: application/json; charset=utf-8" \
-d @request.json \
"https://translation.googleapis.com/v3/projects/PROJECT_NUMBER_OR_ID/locations/global:detectLanguage"

PowerShell

Note: Ensure you have set the GOOGLE_APPLICATION_CREDENTIALS environment variable to the path for your service account private key file.

Save the request body in a file called request.json, and execute the following command:

$cred = gcloud auth application-default print-access-token
$headers = @{ "Authorization" = "Bearer $cred" }

Invoke-WebRequest `
  -Method POST `
  -Headers $headers `
  -ContentType: "application/json; charset=utf-8" `
  -InFile request.json `
  -Uri "https://translation.googleapis.com/v3/projects/PROJECT_NUMBER_OR_ID/locations/global:detectLanguage" | Select-Object -Expand Content

You should receive a JSON response similar to the following:

{
  "languages": [
    {
      "languageCode": "ru",
      "confidence": 1
    }
  ]
}

In the response, languageCode provides the language code of the language detected. confidence is a range from 0 to 1. 1 is 100% confident.

Go

Before trying this sample, follow the Go setup instructions in the Translation quickstart using client libraries. For more information, see the Translation Go API reference documentation.

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import (
	"context"
	"fmt"
	"io"

	translate "cloud.google.com/go/translate/apiv3"
	translatepb "google.golang.org/genproto/googleapis/cloud/translate/v3"
)

// detectLanguage detects the language of a text string.
func detectLanguage(w io.Writer, projectID string, text string) error {
	// projectID := "my-project-id"
	// text := "Hello, world!"

	ctx := context.Background()
	client, err := translate.NewTranslationClient(ctx)
	if err != nil {
		return fmt.Errorf("NewTranslationClient: %v", err)
	}
	defer client.Close()

	req := &translatepb.DetectLanguageRequest{
		Parent:   fmt.Sprintf("projects/%s/locations/global", projectID),
		MimeType: "text/plain", // Mime types: "text/plain", "text/html"
		Source: &translatepb.DetectLanguageRequest_Content{
			Content: text,
		},
	}

	resp, err := client.DetectLanguage(ctx, req)
	if err != nil {
		return fmt.Errorf("DetectLanguage: %v", err)
	}

	// Display list of detected languages sorted by detection confidence.
	// The most probable language is first.
	for _, language := range resp.GetLanguages() {
		// The language detected.
		fmt.Fprintf(w, "Language code: %v\n", language.GetLanguageCode())
		// Confidence of detection result for this language.
		fmt.Fprintf(w, "Confidence: %v\n", language.GetConfidence())
	}

	return nil
}

Java

Before trying this sample, follow the Java setup instructions in the Translation quickstart using client libraries. For more information, see the Translation Java API reference documentation.

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import com.google.cloud.translate.v3.DetectLanguageRequest;
import com.google.cloud.translate.v3.DetectLanguageResponse;
import com.google.cloud.translate.v3.DetectedLanguage;
import com.google.cloud.translate.v3.LocationName;
import com.google.cloud.translate.v3.TranslationServiceClient;
import java.io.IOException;

public class DetectLanguage {

  public static void detectLanguage() throws IOException {
    // TODO(developer): Replace these variables before running the sample.
    String projectId = "YOUR-PROJECT-ID";
    String text = "your-text";

    detectLanguage(projectId, text);
  }

  // Detecting the language of a text string
  public static void detectLanguage(String projectId, String text) throws IOException {

    // Initialize client that will be used to send requests. This client only needs to be created
    // once, and can be reused for multiple requests. After completing all of your requests, call
    // the "close" method on the client to safely clean up any remaining background resources.
    try (TranslationServiceClient client = TranslationServiceClient.create()) {
      // Supported Locations: `global`, [glossary location], or [model location]
      // Glossaries must be hosted in `us-central1`
      // Custom Models must use the same location as your model. (us-central1)
      LocationName parent = LocationName.of(projectId, "global");

      // Supported Mime Types: https://cloud.google.com/translate/docs/supported-formats
      DetectLanguageRequest request =
          DetectLanguageRequest.newBuilder()
              .setParent(parent.toString())
              .setMimeType("text/plain")
              .setContent(text)
              .build();

      DetectLanguageResponse response = client.detectLanguage(request);

      // Display list of detected languages sorted by detection confidence.
      // The most probable language is first.
      for (DetectedLanguage language : response.getLanguagesList()) {
        // The language detected
        System.out.printf("Language code: %s\n", language.getLanguageCode());
        // Confidence of detection result for this language
        System.out.printf("Confidence: %s\n", language.getConfidence());
      }
    }
  }
}

Node.js

Before trying this sample, follow the Node.js setup instructions in the Translation quickstart using client libraries. For more information, see the Translation Node.js API reference documentation.

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/**
 * TODO(developer): Uncomment these variables before running the sample.
 */
// const projectId = 'YOUR_PROJECT_ID';
// const location = 'global';
// const text = 'text to translate';

// Imports the Google Cloud Translation library
const {TranslationServiceClient} = require('@google-cloud/translate');

// Instantiates a client
const translationClient = new TranslationServiceClient();

async function detectLanguage() {
  // Construct request
  const request = {
    parent: `projects/${projectId}/locations/${location}`,
    content: text,
  };

  // Run request
  const [response] = await translationClient.detectLanguage(request);

  console.log('Detected Languages:');
  for (const language of response.languages) {
    console.log(`Language Code: ${language.languageCode}`);
    console.log(`Confidence: ${language.confidence}`);
  }
}

detectLanguage();

Python

Before trying this sample, follow the Python setup instructions in the Translation quickstart using client libraries. For more information, see the Translation Python API reference documentation.

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from google.cloud import translate


def detect_language(project_id="YOUR_PROJECT_ID"):
    """Detecting the language of a text string."""

    client = translate.TranslationServiceClient()

    location = "global"

    parent = f"projects/{project_id}/locations/{location}"

    # Detail on supported types can be found here:
    # https://cloud.google.com/translate/docs/supported-formats
    response = client.detect_language(
        content="Hello, world!",
        parent=parent,
        mime_type="text/plain",  # mime types: text/plain, text/html
    )

    # Display list of detected languages sorted by detection confidence.
    # The most probable language is first.
    for language in response.languages:
        # The language detected
        print("Language code: {}".format(language.language_code))
        # Confidence of detection result for this language
        print("Confidence: {}".format(language.confidence))

Additional languages

C#: Please follow the C# setup instructions on the client libraries page and then visit the Translation reference documentation for .NET.

PHP: Please follow the PHP setup instructions on the client libraries page and then visit the Translation reference documentation for PHP.

Ruby: Please follow the Ruby setup instructions on the client libraries page and then visit the Translation reference documentation for Ruby.

Additional resources

• For help on resolving common issues or errors, see the Troubleshooting page.