Learn English – Pronunciation of “Einstein”

First off, Albert Einstein's surname is pronounced with a sh sound in his native Germany, due to the second syllable of his surname beginning with "st" (literally, his name means "one stone"). The vowel grouping ei in German is pronounced similar to the English "eye", though with less emphasis on the first part of the diphthong. (See the Wikipedia entry for more details.)

As for the typical English pronunciation of his name ("ine-stine"), of the two parts that are not typical in English, one was retained when he migrated to the U.S. later in life, the other was not. Of the many German migrant families whose surname ended in -stein, some chose to keep the original ei pronunciation (-stine) while others more or less gradually switched to pronouncing it -steen for a variety of reasons. While the ei sound is of course quite easy for English-only speakers to pronounce, the sht sound is less natural.

As British English speakers (and please don't crucify me for saying this, see the disclaimer below) arguably learn fewer foreign languages than other Europeans, and even fewer Americans learn a second language, some pronunciations of foreign names are gradually adapted, and sometimes the spelling is modified to make the name "less foreign". (I have wondered many times whether it is worth the battle to continue insisting that my Germanic surname, which ends in -mann, keep its second n at the end. Many an authority or government agency has gotten this wrong and it has caused me some major headaches.)

In Einstein's case, I can only assume - and this is pure conjecture on my part - that because he became well-known in the U.K. and U.S. long before his emigration, people's minds about how to pronounce his surname were made up and he either did not mind, was too polite, or simply gave up trying to correct them. My point being that changes in spelling or pronunciation of migrants have little to do with consistency and far more with convenience.

_{Disclosure/Disclaimer: this post has been heavily edited after a bashing for being "baseless, biased, and not helpful for answering the question". Though I live in Australia, I'm a native speaker of both English and German (as well as one other language), have learned a couple of others well enough to muddle my way through a conversation, and have a very basic understanding of a few more. Please don't think I'm stating my linguistic background to brag or to claim to be an expert on linguistics (my sister is the one who has a Ph.D. in linguistics), nor that I intend to offend anyone when I say that English speakers typically learn or speak fewer foreign languages than native speakers - and yes, I do realise that frequenters of EL&U do not represent "typical" English speakers. I am also not judging this imbalance of foreign languages in any way, I will happily leave that to others, some of whom are far more prominent than I.}