The Hot Questions English filter isn't working. I have seen all of the following in the Hot Questions list since yesterday:
Neither Italian nor Spanish sites are intentionally omitted - those sites are for English speakers who are learning those languages, so there's no expectation that these aren't of interest because the titles are guaranteed to be in a different language.
Russian Stack Overflow was excluded yesterday, the questions list will catch up as cache expires.
(Having said that, this is not so much an exclusion as it's a check for a certain amount of English in the title and body - I don't have the specifics in front of me - so it may make sense to flip this check on for language learner sites. But that's a feature-request. I don't know off-hand what the impact would be and whether the change is desirable. :))