I’ve met plenty of Japanese who speak fantastic English. Everyone had to study it from Jr. High here and, starting a couple of years ago, starting in elementary school. Pronunciation is very hit or miss since many of the teachers in Japan can’t even hear the difference between l/r and the like sometimes and ALT (assistant language teachers, typically native speakers of English) are rarely allowed to drive things and push more from what I read.

Many Japanese who went to uni had to pass an English test section to do so from what I understand. You can look up sample questions on the web. As such, many can read English to a certain degree, but output and listening are often issues.

My wife hated English class and never paid much attention. She’s working her way through a textbook now and she finds various aspects difficult (looking at you do as in do you like potatoes – WTF is the do doing there? Why not like you potatoes?!) The alphabet portion, though, is not an issue in itself. Pronunciation requires a lot of work but I think that’s because English orthography sucks. However, if you grow up where a whole range of sounds just map to one in your language (l/r problem again), you don’t learn to differentiate between the various points in that range and can’t hear that difference without a lot of work. Definitely so for sounds that don’t exist at all. Many people going into Japanese have trouble differentiating germinate consonants and tsu vs su.