If he was world reknowned there must be some video, even just one of him actually talking. Can you find one?

Oh and I mean talking coherently.

More proof.

Hawking's speech deteriorated, and by the late 1970s he could only be understood by his family and closest friends. To communicate with others, someone who knew him well would translate his speech into intelligible speech.[64]

64. Ferguson 2011, pp. 81–82.

1966–1975

In his work, and in collaboration with Penrose, Hawking extended the singularity theorem concepts first explored in his doctoral thesis. This included not only the existence of singularities but also the theory that the Universe might have started as a singularity. Their joint essay was the runner-up in the 1968 Gravity Research Foundation competition.[145][146] In 1970 they published a proof that if the Universe obeys the general theory of relativity and fits any of the models of physical cosmology developed by Alexander Friedmann, then it must have begun as a singularity.[147][148][149] In 1969, Hawking accepted a specially created Fellowship for Distinction in Science to remain at Caius.[150]

In 1970 Hawking postulated what became known as the second law of black hole dynamics, that the event horizon of a black hole can never get smaller.[151] With James M. Bardeen and Brandon Carter, he proposed the four laws of black hole mechanics, drawing an analogy with thermodynamics.[152] To Hawking's irritation, Jacob Bekenstein, a graduate student of John Wheeler, went further—and ultimately correctly—to apply thermodynamic concepts literally.[153][154] In the early 1970s, Hawking's work with Carter, Werner Israel and David C. Robinson strongly supported Wheeler's no-hair theorem that no matter what the original material from which a black hole is created it can be completely described by the properties of mass, electrical charge and rotation.[155][156] His essay titled "Black Holes" won the Gravity Research Foundation Award in January 1971.[157] Hawking's first book, The Large Scale Structure of Space-Time. written with George Ellis, was published in 1973.[158]

Beginning in 1973, Hawking moved into the study of quantum gravity and quantum mechanics.[159][158] His work in this area was spurred by a visit to Moscow and discussions with Yakov Borisovich Zel'dovich and Alexei Starobinsky, whose work showed that according to the uncertainty principle rotating black holes emit particles.[160] To Hawking's annoyance, his much-checked calculations produced findings that contradicted his second law, which claimed black holes could never get smaller,[161] and supported Bekenstein's reasoning about their entropy.[162][160] His results, which Hawking presented from 1974, showed that black holes emit radiation, known today as Hawking radiation, which may continue until they exhaust their energy and evaporate.[163][164][165] Initially, Hawking radiation was controversial. However by the late 1970s and following the publication of further research, the discovery was widely accepted as a significant breakthrough in theoretical physics.[166][167][168] In March 1974, a few weeks after the announcement of Hawking radiation, Hawking was invested as a Fellow of the Royal Society, one of the youngest scientists to be so honoured.[169][170]

Hawking was appointed to the Sherman Fairchild Distinguished visiting professorship at the California Institute of Technology (Caltech) in 1970. He worked with a friend on the faculty, Kip Thorne,[171] and engaged him in a scientific wager about whether the dark star Cygnus X-1 was a black hole. The wager was a surprising "insurance policy" against the proposition that black holes did not exist.[172] Hawking acknowledged that he had lost the bet in 1990, which was the first of several that he was to make with Thorne and others.[173] Hawking has maintained ties to Caltech, spending a month there almost every year since this first visit.[174]

1975–1990

Hawking returned to Cambridge in 1975 to a more advanced academic senior position —as reader. The mid to late 1970s were a period of growing public interest in black holes and of the physicist who was studying them. Hawking was regularly interviewed for print and television.[175][176] He also received increasing academic recognition of his work.[42] In 1975 he was awarded both the Eddington Medal and the Pius XI Gold Medal, and in 1976 the Dannie Heineman Prize, the Maxwell Prize and the Hughes Medal.[177][178] Hawking was appointed a professor with a chair in gravitational physics in 1977.[58] The following year he received the Albert Einstein Medal and an honorary doctorate from the University of Oxford.[36][42]

36. Larsen 2005, p. xiv.

42. Ferguson 2011, p. 92.

58. Ferguson 2011, p. 91.

145. White & Gribbin 2002, p. 101.

146. Ferguson 2011, p. 61,64.

147. Ferguson 2011, pp. 64–65.

148. White & Gribbin 2002, pp. 115–16.

149. Hawking, Stephen; Penrose, Roger (1970). "The Singularities of Gravitational Collapse and Cosmology". Proceedings of the Royal Society A 314 (1519): 529–548. Bibcode:1970RSPSA.314..529H.

150. Ferguson 2011, p. 49.

151. Ferguson 2011, pp. 65–67.

152. Larsen 2005, p. 38

153. Ferguson 2011, pp. 67–68.

154. White & Gribbin 2002, pp. 123–24.

155. Larsen 2005, p. 33.

156. R. D. Blandford (30 March 1989). "Astrophysical Black Holes". In S. W. Hawking and W. Israel. Three Hundred Years of Gravitation. Cambridge University Press. p. 278.

157. Larsen 2005, p. 35.

158. Ferguson 2011, p. 68.

159. Larsen 2005, p. 39.

160. White & Gribbin 2002, p. 146.

161. Ferguson 2011, p. 70.

162. Larsen 2005, p. 41.

163. Hawking, Stephen W. (1974). "Black hole explosions?". Nature 248 (5443): 30–31.

164. Hawking, Stephen W. (1975). "Particle creation by black holes". Communications in Mathematical Physics 43 (3): 199–220.

165. Ferguson 2011, pp. 69–73.

166. Ferguson 2011, pp. 70–74.

167. Larsen 2005, pp. 42–43.

168. White & Gribbin 2002, pp. 150–51.

169. Larsen 2005, p. 44.

170. White & Gribbin 2002, p. 133.

171. Ferguson 2011, pp. 82, 86.

172. Ferguson 2011, pp. 86–88.

173. Ferguson 2011, pp. 150,189, 219.

174. Ferguson 2011, p. 95.

175. Ferguson 2011, p. 90.

176. White & Gribbin 2002, pp. 132–33.

177. White & Gribbin 2002, p. 162.

178. Larsen 2005, pp. xv.

Sources

Ferguson, Kitty (2011). Stephen Hawking: His Life and Work. Transworld. ISBN 978-1-4481-1047-6.

White, Michael; Gribbin, John (2002). Stephen Hawking: A Life in Science (2nd ed.). National Academies Press. ISBN 978-0-309-08410-9.

Larsen, Kristine (2005). Stephen Hawking: a biography. ISBN 978-0-313-32392-8.

and a couple scientific journals.