> Does Enlgish routinely localize foreign alphabet names?

All the time. In terms of pronunciation, the English love adding extra vowels and elongating others when pronouncing foreign words, especially names.

A classic example, which even the English are aware of and like to laugh about:

"Una cerveza por favor" will turn into "Ooona cervezaa pour favor"

but that's because English lacks pure long mid vowels ('e' and 'o' are diphthongs in English). But has nothing really to do with op's question.

It's only Greek (as far as I know), and because of the history of teaching Ancient Greek in schools in Britain. See https://en.wikipedia.org/wiki/Pronunciation_of_Ancient_Greek...

Note that the Latin alphabet is pronounced inconsistently all across Europe. I'm sure any 14 year old can precisely spell their name out loud in English, since they're going to be examined on it, but later in life people forget the difference between their own language and English, especially the vowels.

For example when speaking English, I find Danish people will mix up E and I if I spell a word with English pronunciation, and Danish people speaking English will often use the Danish pronunciation of J, K, Q, Y (roughly yoll, co, coo, oo).

Doing the Greek course on Duolingo, I discovered that several of the pronunciations for Greek letters I learned in college are incorrect. In gross terms (I don't really know how to use IPA to be more specific here): beta -> veta, delta -> thelta, for example.

It's a result of the Great English Vowel Shift which affected long vowels, and has affected pronunciation of Roman/English letter names (amongst other things) as well (think about the oddness of the name of the letter A in English, for instance) .

The comments about the Great Vowel Shift are correct, but I would also like to add that in English we already pronounce the Latin letter "P" /pi/, and it would hardly do to have the two pronounced the same way given the importance of ratio in math. So even if we wanted to adopt the Greek pronunciation, we probably wouldn't because of the confusion it would generate.

Just a wild guess, but perhaps it's part of a vowel shift either in modern Greek, or modern English.

I know UK (bee-ta) and USA (bay-ta) pronounce Beta differently but am slightly ashamed to say I don't know how modern Greeks pronounce it. I understand it's derived from Hebrew's Beth, though?

Language is a constant curiosity.

"In Ancient Greek, beta represented the voiced bilabial plosive /b/. In Modern Greek, it represents the voiced labiodental fricative /v/."

For centuries, and probably still today, the language taught at school was Ancient Greek -- that's where I learnt the pronunciations. I don't know if pi had a similar change in Greek pronunciation.

https://en.wikipedia.org/wiki/Beta

In Greek letter β is actual pronounced like Vee-ta and in words it's read like latin V (Babylon is pronounced like Vah-vee-lon).

Modern, Ancient, or both?

https://en.wikipedia.org/wiki/Great_Vowel_Shift is why.