Question: what is the most common language spoken in bangladesh
[{'answer': 'Bengali', 'provenance': [{'wikipedia_id': '10785107', 'title': 'Languages of Bangladesh', 'start_paragraph_id': 1, 'start_character': 23, 'end_paragraph_id': 1, 'end_character': 30, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]