Which is correct: "had gotten along with" or "had got along with"?

Question

I once texted a sentence like "It reminded me of a friend whom I had got along with," and someone pointed out that I should use "a friend whom I had gotten along with."

It's a bit hard for me to comprehend their difference and how to use them correctly. As I was checking, I noticed the answer from a website (link), which sounds to me that both of them are correct, I guess. So, what are your opinions?

From comments:

I know what "get along with somebody" means, but have no idea what "get" means in this phrase. I was told that with those idioms like "get along with," "come about," we can't try to figure them out by understanding the separate word itself.

The links seem to suggest: it depends on the meaning of "get". When "get" means to "become," I should say "have gotten." When "get" in a sentence means to "receive, obtain," I should say "have got", for example, I've got a cake. Am I right in understanding this way?

But I don't know what "get" means in the idiom "get along with somebody." Does it mean to "become along with somebody"? Seems that it doesn't make sense. Does it mean to "obtain along with somebody"? The rules contain so many details that I can't grasp. Maybe you can tell me the answer directly, I guess?

Answer 1

In simple words, in American English verb conjugation for "get" goes: get, got, gotten. "Got" is the past tense, and "gotten" is the past participle.

In British English, "gotten" has gotten (become) a bit dated and is no longer used as the past participle of "get". So the list goes: get, got, got.

In your example, if you follow the American English tradition you would say "a friend whom I had gotten along with", and if you follow the British English tradition it is "a friend whom I had got along with", because "get alone with someone" is a set phrase and here you need the past participle following "have/had".

However, things get a little tricky if you talk about "have got something" in American English. "Got" is also used in American English in the phrase "have got" or it's contraction "'ve got". I won't get into that since that is not what you are asking. Read these posts:

"Gotten" versus "got"

Should I use “got” or “gotten” in the following sentence?

These discussions might be a little hard to follow. All you need to remember is "have got" is a unique phrase and a set usage. And it means the same as "have" (possession).

Look what I've got here. (or more casually Look what I got here.)

= Look what I have here.

Your example is not an instance of "have got" and has nothing to do with "have something". It is "have" + "get along with". In this case you need to conjugate "get" and use its past participle. That is why you say "a friend I had gotten along with" (if you follow American English). That is because "get along with someone" is another phrase in its own right.