I hesitate to offer an opinion on this because I'm a white native English speaker, but my wife is from Japan and I've been studying Japanese for long time so I feel I have at least a little perspective outside the one I was born with.

First, if were true that Asian accents are definitively harder to understand than European accents all else being equal, I'd just have to put it down to racism, though not necessarily the malicious kind, more the ignorant kind.

But I'm not willing to accept that as true, at least not as a rule. For one thing, while Japanese and Korean have a lot of linguistic similarities, Mandarin Chinese is extremely different in syntax, phonemes, and pretty much everything else besides Chinese characters, which don't matter in speech. And then there are many other Asian languages which have their own unique points, so it's unfair to lump them all together as though Asian accents all sounded the same.

The one thing I would say is that in general, European school systems equip their youth to speak English at a much higher standard than do Japanese schools. The result is that many Europeans who travel to North America are better able to form grammatical sentences than Japanese people, even if their accents are far from native. Part of that may be due to the fact that Japanese and English are much farther apart than are, say, French and English. Scandinavians often sound nearly native in English, and it's no wonder because their languages are so closely related to English, as I learned from studying Norwegian. But part of it may be because the Japanese school system just isn't very good at teaching English. (I say this from observation. I have no opinion of the school systems in other Asian countries.)

Anyway, this is a very difficult problem to quantify, if it exists at all. The original poster, Dyske, didn't even say whether he himself had a hard time being understood or if he was just talking about other Asian people. Since there are many people of Asian descent where I live who were born here and sound like any other native English speakers, and have no difficulties being understood, I'm not sure if this is a real phenomenon (all else being equal) or not.

As to Indian subcontinent accents being hard to understand. I'm sure it's not contextual information. There are many accents within the English language that are hard for North Americans to understand without exposure, and the South Asian accent is just one of them. Others include Scottish, Caribbean, and New Zealand accents. Even British movies needed subtitles or dubbing in the early days of talkies because North American ears had not yet been familiarized with that way of speaking English.

And that careless usage is why he had to resign. Among other things.

I can't answer this question, but it may be left over from old English. I note that in Norwegian (a cousin from the Old English side), there are two forms of "home": hjem and hjemme. The former is used when movement is involved: "Jeg drar hjem." [I'm going home.] The latter is used when someone is stationary: "Jeg er hjemme." [I'm (at) home.] Similar constructions are used for the Norwegian words for "up" and "down".

Perhaps "home" is so basic to us, that our language treats it as a direction (like "up" and "down") rather than as a place.

"Sold only if they used to sell them but they do not sell them anymore." Well, if you were telling about something that happened today, that's true.

But if you were telling a story from the past, you'd say, "I found a store that sold ferrets." And that doesn't mean that they no longer do so.

The word "his" is used in two senses, parallel to "my/your" and also to "mine/yours".

Let's not use "cat" in this example since cats are rarely capable of doing what we want them to. Let's use "child" instead.

That is my/his child.
That child is mine/his.

Let my child come in.
Let mine come in.

Let his child come in.
Let his come in.

Grammatically, I think it's fine in the right context.

Dyske, you say it should be "is" because it matches "the answer". OK, but what if the number changes, mid-sentence: "It is they who are the problem." Doesn't that sound more natural than "It is they who is the problem"? "They" is plural; "the problem" is singular. Plural wins in this case.