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Set Language Manually

Specify a dominant language via language_code to route your request to the best available speech model for that language.

For the complete documentation index, see llms.txt

cURL quickstart — Set Language Manually

# Submit transcription with a specific language_code
curl  \
  --header "Authorization: YOUR_API_KEY" \
  --header "Content-Type: application/json" \
  --data '{
    "audio_url": "",
    "speech_models": ["universal-3-pro", "universal-2"],
    "language_code": "es"
  }'

# Poll for result (replace TRANSCRIPT_ID)
curl  \
  --header "Authorization: YOUR_API_KEY"

The speech_model_used field in the response indicates which model processed the request.

US & EU

If you already know the dominant language of your audio file, you can use the language_code parameter to specify the language rather than using Automatic language detection.

When you specify a language, the system automatically routes your request to the best available model based on that language and the models you provide in the speech_models parameter. For example, with speech_models: ["universal-3-pro", "universal-2"], the system will use Universal-3 Pro for languages it supports and automatically fall back to Universal-2 for all other languages. You can check which model processed your request using the speech_model_used field in the response. See the Model selection page for more details.

If you set language_code and enable a feature that isn't supported for that language, the API will reject the request with an error such as "The following models are not available in this language: speaker_labels". Check the Supported Languages & Features page to verify which features are available for your language before submitting a request.

import assemblyai as aai

aai.settings.api_key = "<YOUR_API_KEY>"

# audio_file = "./local_file.mp3"
audio_file = ""

config = aai.TranscriptionConfig(
    speech_models=["universal-3-pro", "universal-2"],
    language_code="es"
)

transcript = aai.Transcriber(config=config).transcribe(audio_file)

if transcript.status == "error":
  raise RuntimeError(f"Transcription failed: {transcript.error}")

print(transcript.text)

import requests
import time

base_url = ""

headers = {
    "authorization": "<YOUR_API_KEY>"
}

with open("./my-audio.mp3", "rb") as f:
  response = requests.post(base_url + "/v2/upload",
                          headers=headers,
                          data=f)

upload_url = response.json()["upload_url"]

data = {
    "audio_url": upload_url, # You can also use a URL to an audio or video file on the web
    "speech_models": ["universal-3-pro", "universal-2"],
    "language_code": "es"
}

url = base_url + "/v2/transcript"
response = requests.post(url, json=data, headers=headers)

transcript_id = response.json()['id']
polling_endpoint = base_url + "/v2/transcript/" + transcript_id

while True:
  transcription_result = requests.get(polling_endpoint, headers=headers).json()

  if transcription_result['status'] == 'completed':
    print(f"Transcript ID: {transcript_id}")
    break

  elif transcription_result['status'] == 'error':
    raise RuntimeError(f"Transcription failed: {transcription_result['error']}")

  else:
    time.sleep(3)

import { AssemblyAI } from "assemblyai";

const client = new AssemblyAI({
  apiKey: "<YOUR_API_KEY>",
});

// const audioFile = './local_file.mp3'
const audioFile = "";

const params = {
  audio: audioFile,
  speech_models: ["universal-3-pro", "universal-2"],
  language_code: "es",
};

const run = async () => {
  const transcript = await client.transcripts.transcribe(params);

  console.log(transcript.text);
};

run();

import fs from "fs-extra";

const baseUrl = "";

const headers = {
  authorization: "<YOUR_API_KEY>",
};

const path = "./my-audio.mp3";
const audioData = await fs.readFile(path);
let res = await fetch(`${baseUrl}/v2/upload`, {
  method: "POST",
  headers,
  body: audioData,
});
if (!res.ok) throw new Error(`Error: ${res.status}`);
const uploadResponse = await res.json();
const uploadUrl = uploadResponse.upload_url;

const data = {
  audio_url: uploadUrl, // You can also use a URL to an audio or video file on the web
  speech_models: ["universal-3-pro", "universal-2"],
  language_code: "es",
};

const url = `${baseUrl}/v2/transcript`;
res = await fetch(url, {
  method: "POST",
  headers: { ...headers, "Content-Type": "application/json" },
  body: JSON.stringify(data),
});
if (!res.ok) throw new Error(`Error: ${res.status}`);
const response = await res.json();

const transcriptId = response.id;
const pollingEndpoint = `${baseUrl}/v2/transcript/${transcriptId}`;

while (true) {
  res = await fetch(pollingEndpoint, { headers });
  if (!res.ok) throw new Error(`Error: ${res.status}`);
  const transcriptionResult = await res.json();

  if (transcriptionResult.status === "completed") {
    console.log(transcriptionResult.text);
    break;
  } else if (transcriptionResult.status === "error") {
    throw new Error(`Transcription failed: ${transcriptionResult.error}`);
  } else {
    await new Promise((resolve) => setTimeout(resolve, 3000));
  }
}

See the Supported Languages & Features page for all supported languages and their codes.