hiː kəntˈɪnjuːd ðə wˈɜːk ʌntˈɪl nˈaɪntiːnhˈʌndɹɪd twˈɛnti ˈeɪt, sɚvˈeɪɪŋ pˈiːpəl əkɹˌɑːs ðə bɹˈɪɾɪʃ ˈɪndiən tˈɛɹɪtˌoːɹi, dˈɑːkjuːməntɪŋ spˈoʊkən lˈæŋɡwɪdʒᵻz, ɹᵻkˈoːɹdɪŋ vˈɔɪsᵻz, ɹˈɪʔn̩ fˈɔːɹmz ænd wʌz ɹᵻspˈɑːnsᵻbəl ɪn dˈɑːkjuːməntɪŋ ˌɪnfɚmˈeɪʃən ˌɔn wˈʌnhˈʌndɹɪd sˈɛvənti nˈaɪn lˈæŋɡwɪdʒᵻz, dᵻfˈaɪnd baɪ hˌɪm θɹuː ɐ tˈɛst ʌv mjˈuːtʃuːəl ˌʌnɪntˌɛlɪdʒəbˈɪlᵻɾi, ænd fˈaɪvhˈʌndɹɪd fˈoːɹɾi fˈoːɹ dˈaɪəlɛkts wˌɪtʃ hiː plˈeɪst ɪn fˈaɪv lˈæŋɡwɪdʒ fˈæmɪliz.
He continued the work until 1928, surveying people across the British Indian territory, documenting spoken languages, recording voices, written forms and was responsible in documenting information on 179 languages, defined by him through a test of mutual unintelligibility, and 544 dialects which he placed in five language families.