Language Detector

Language Detector is a tool for detecting languages of the chosen indices documents. It uses langdetect python module. This is useful for getting a quick overview of the languages presented in your dataset and parse out documents in a certain language for future work.




Name of the Language Detector application task. This is necessary only for differentiating between all the Language Detector tasks in the project.


List of Elasticsearch indices containing the documents to analyze. NB! Indices should be formatted as list of dicts, where key = “name” and value = <index_name>, e.g:

[{"name": "my_dataset"}]

List of field names (as strings) that are containing the content to analyze.


The query restricting the set of documents to analyze. In the API, the query should be formatted as a JSON string. In the GUI saved searches can be used. By default empty and all the documents in the chosen indices are then analyzed.


For creating a new Language Detector task, navigate to “Tools” -> “Language Detector” and click on the button “CREATE” in the upper left corner of the page. A new window with the title “Apply Language Detector task” opens as a result. Fill all the required fields and then click on the button “Create” in the bottom right corner of the window (Fig. 58). The new Language Detector task should now appear as a new row in the list of Language Detector tasks on the same page (if not, try refreshing the page).


Fig. 58 Language Detector creation window

After the task has finished (status is “completed”), you can view the results in Search. The output of language analysis is stored in the field <field_concept> <source_field>_mlp.language_detected.


Endpoint for /api/v1/ : /projects/{project_pk}/lang_index/

Endpoint for /api/v2/ : /projects/{project_pk}/lang_index/


curl -X POST "http://localhost:8000/api/v2/projects/1/lang_index/" \
-H "accept: application/json" \
-H "Content-Type: application/json" \
-H "Authorization: Token 8229898dccf960714a9fa22662b214005aa2b049" \
-d '{
        "indices": [{"name": "index_name"}],
        "description": "job_description",
        "field": "field_name_to_detect_on"


  "id": 6,
  "url": "http://localhost:8000/api/v2/projects/1/lang_index/6/",
  "author_username": "test_user",
  "indices": [
     "id": 3949,
     "is_open": true,
     "url": "http://localhost:8000/api/v2/elastic/index/3949/",
     "name": "index_name",
     "description": "",
     "added_by": "test_user",
     "test": true,
     "source": "",
     "client": "",
     "domain": "",
     "created_at": "2021-07-27T13:56:46.118000+03:00"
  "description": "job_description",
  "task": {
     "id": 163542,
     "status": "completed",
     "progress": 100.0,
     "step": "",
     "errors": "[]",
     "time_started": "2021-07-27T16:58:46.886043+03:00",
     "last_update": null,
     "time_completed": "2021-07-27T16:59:09.632845+03:00",
     "total": 0,
     "num_processed": 0
  "query": "{\"query\": {\"match_all\": {}}}",
  "field": "field_name_to_detect_on"