Possible Clues:

• Underdeveloped countries
• Underdeveloped nations
• Underdeveloped regions with linguistics unit inspiring learner after degree
• Coming from the sun, the earth is a poor place
• Like couple in final clue touring large part of the globe
• Dame Thora in address, perhaps, with promise to go round fifty developing nations
• Winner missing in this sphere in Latin America, perhaps
• Lord with doctor shortly touring developing nations
• Thora's pupil in promise to be developed
• Developing nations, collectively