Grierson attended the Oriental Congress in 1886 at Vienna and proposed the idea of a formal linguistic in India. Grierson was a delegate of the Royal Asiatic Society along with Dr Theodor Duka, Albert Terrien de Lacouperie, Cecil Bendall, and R. N. Cust. At the Congress it was noted that the number of Indian languages was unknown with estimates varying from twenty to 250. A resolution was passed urging the Government to undertake a 'deliberate systematic survey of the languages of India.' The signatories included Karl Bühler, Max Müller, Monier Williams and Grierson. The recommendation was made to the British Government and in 1898 he was appointed Superintendent of the newly formed Linguistic Survey of India. For the survey a standard set of materials were sought. He had government officials collect material for every language, dialect, and subdialect, going from village to village and sampling across the classes and sexes. He provided forms and instructional material to his correspondents. He sought a version of the parable of the prodigal son, oral narratives and a predefined list of 241 words and phrases (this list had been made by Sir George Campbell in 1866). The parable was chosen because 'it contains the three personal pronouns, most of the cases found in the declension of nouns, and the present, past, and future tenses of the verb'. The survey classified the languages of 290,000,000 people. In 1900 he moved to England "for convenience of consulting European libraries and scholars". By 1903 most of the data had come in and he retired from the Indian Civil Service. He spent the following thirty years editing the enormous amount of material gathered and worked briefly in collaboration with the Norwegian linguist Sten Konow (who contributed to volume III on Tibetan languages). On 8 May 1928 the completion of the Linguistic Survey of India was celebrated at the Criterion Restaurant by the Royal Asiatic Society of Great Britain and Ireland with Lord Birkenhead proposing the toast.