I understand の can be a possessive like たなかさんの犬 (Tanaka’s dog) or a restriction on a following noun like こうこうのせんせい (high school teacher).
But is it correct Japanese grammar to stretch this out to more than two nouns?
For example: たなかさんのお母さんの犬 (Tanaka’s mom’s dog)
Or
イギリス人のこうこうのせんせい (British high school teacher)
My say would be yes.
I’m not sure about stretching it out past 3 nouns. Like saying 私の友人の妹のおやつ (my friend’s little sisters snack)
I guess it’s a bit like と in that regard. There’s really only so many you can string along with it.
Yep. There’s a point at which the meaning may start to get ambiguous (i.e. does AのBのC mean Aの(BのC) or (AのB)のC), but it’s perfectly grammatical.
You can, but it gets unwieldy after a few, and most natives would start to rephrase things.
Just for clarification, for the meaning you described, this first の in this example is a different kind of の. It’s a valid construction, but the grammar works differently.
The literal meaning with the original type of の you were talking about would be “a British person’s high school teacher.”
風の谷のナウシカ : Nausicaa of the valley of the wind 
I raise you my 桜の森の満開の下 
(Translated in English by In the Forest, Under Cherries in Full Bloom)
Not sure if we can find any examples with four の though.
I came across this cute phrase the other day:
あなたは私の掌中の玉
ありがとうございます！
This all helps. I didn’t see examples of these in the textbook past two nouns so it had me second guessing
You have the exact same phenomenon in English with possessives: “My brother’s roommate’s wife’s dad’s car is a Mercedes”. It’s not wrong per se but it becomes unwieldy and hard to parse if you abuse it.
AのBのC is certainly not uncommon though. Here’s a random example:
試験のための魔法
“Test’s sake’s magic” or more naturally “magic for the sake of (in order to pass) the test”
As @Belthazar points out, I think it’s mostly used when there’s no possible ambiguity. Here it has to be 【試験のため】の魔法 because 試験の【ための魔法】 doesn’t really make sense.
This conversation is making me want to watch a Japanese dub of Spaceballs now just to see how they handle it lol
Lonestar. I am your father’s brother’s nephew’s cousin’s former roommate.
What does that make us?
Absolutely nothing.
Searching for 「の 連続」 led to this article:
The author proscribes using の more than twice in a row, arguing that it makes the sentence sound clumsy. They then provide strategies to replace の with other constructs like に関する or が持っている.
ありがとう this is exactly what I’m looking for
Though of course when you find style-advice articles saying “don’t write like this” that implies that at least some people do happily write and speak that way sometimes. There’s not usually much need to argue against things that are truly not grammatical 
Yeah absolutely, the author even mentions that it sounds 口語 which implies that you can actually hear it in casual discussion.
Hah, that exact exchange was already crossing my mind.
So I turned to Google for a subtitle file. Dunno if this is an official translation, but it’s at least a translation:
DH: 殺す前に、君に言わなきゃいけない事がある
LS: 何？
DH: 私は君の父の兄の甥の従妹の元ルームメイトだ
LS: それで俺たちの関係は？
DH: 赤の他人だ！
DH: もう殺すからそれ以上になる事もない
DH: 死ぬ覚悟を
So the punchline is mildly different, but their relationship is the same.
Yah, English grammar is full of people going “you can’t end sentences with a preposition!” and “you can’t split infinitives!”, but neither of those is actually a rule.
