Why do several countries have names in their own languages that are different than those used by most foreign countries like Germany Hungary China and India?

Answer 1

Primarily cultural and historical reasons.

The name "Germany" comes from the Roman name Germania, which was applied to all the people living above the Alps at the time of the Roman Empire. The German name for Germany, Deutschland, implies that it is the land of the "Deutsch," or the German people. This is why people from the Netherlands are still called "Dutch" in English, because they are a Germanic people and speak Germanic language.

As for the others:

Hungary - "mid-15c., probably lit. "land of the Huns," who ruled a vast territory from there under Attila in the Dark Ages; from M.L. Hungaria, from Medieval Gk. Oungroi, the name applied to the people whose name for themselves we transliterate as Magyars. Also related are Fr. Hongrie, Ger. Ungarn, Rus. Vengriya, Ukr. Ugorshchina, but the Turkish name for the country, Macaristan, reflects the indigenous name."

India - Old English, from L. India, from Gk. India"region of the Indus River," later used of the region beyond it, from Indos "Indus River," from O.Pers. Hindu, the name for the province of Sind, from Skt. sindhu "river." The more common M.E. form was Ynde or Inde, From French (see Indies). India began to prevail 16c., perhaps under Spanish or Portuguese influence.

China - Asian country, 1550s, probably ultimately from Skt. Cina-s "the Chinese" (earliest European usage is in Italian, by Marco Polo), perhaps from Qin dynasty, which ruled 3c. B.C.E. Latinized as Sina, hence sinologist. The Chinese word for the country is Chung-kuo, lit. "the Middle Kingdom."