"A thousand devils!"

Swedish: Many mild curse words (similar to "darn") are just numbers (or old-fashioned ways to say numbers):

• Sjutton också! ("Seventeen also!")
• Tusan! ("A thousand!")
• Attans! ("Eighteen!")

Apparently, this came from expressions like "A thousand devils!", but which were then shortened and mild into just the number. "Sjujävla" (seven-deviled?) is still used as an intensifier. TypingLobster

Tapestry. 

In Swahili, only three colors have "direct" words: black (nyeusi), white (nyeupe), and red (nyekundu).

All other colors are comparatives, e.g.:

green - rangi ya kijani: "the color of leaves"

gray - rangi ya kijivu: "the color of ashes"

maroon -rangi ya damu ya wazee: "the color of the blood of old people." mlimame

Traditionally. 

The Navajo word for tank is "chidí naaʼnaʼí beeʼeldǫǫh bikááʼ dah naaznilígíí". Traditionally Navajo does not use foreign words and instead forms its own using simpler words, and so the word literally is "a car that crawls with a gun on which people sit".

For those asking, the word car is an onomatopoeia of a ford model T engine and the word gun from the word 'to explode'.

https://en.wiktionary.org/wiki/chid%C3%AD_naa%CA%BCna%CA%BC%C3%AD_bee%CA%BCeld%C7%AB%C7%ABh_bik%C3%A1%C3%A1%CA%BC_dah_naaznil%C3%ADg%C3%AD%C3%AD dario606

Explain Celine.

In French French the word "gosses" means children, but in Québécois French that word means testicles, so if there's an old guy who's very enthusiastic about showing you a photo of his gosses, better pray he's French. Callalilly45

For the Love of Liver. 

Something I find funny about Farsi is the saying "jeegaret-o bokhoram" which is an expression meaning "I love you" but it literally means "I want to eat your liver". Similarly "jeegare mani" means "You are my liver", though this one makes a bit more sense because it's like saying "I love you so much you're a part of me".

Edit: Looks like there are even more liver sayings. "Jeegaret besham" means "I'll be your liver"/"I'll do anything for you". There's also "kheyli jeegari" which means something like "You're such a cool person" but it hilariously translates to "You really are a liver". Apparently all this is because the liver is such an important organ, like the person is important to you. Hotrod20006

Buy a Vowel.

In Romanian, you can build a sentence out of vowels only: "Eu iau o oaie" - "I take a sheep"

EDIT: As publicly requested, here's an attempt to pronounce this in English (just not very accurate):

Yeaw yow oh wa-ye. Vladimir-the-Great

Billions. 

I learned today that a billion in Spanish isn't the same as a billion in English. sololloro

Edit: For context, I'm American and I was talking to my Colombian coworker. Apparently the "other billion" is more universal than I thought and Americans are just...wrong. Which isn't surprising!

Even in English, you get the traditional British billion (which no one really uses any more) and the American billion. FakeNathanDrake

The King's Speech. 

The Korean alphabet was single-handedly invented by the King in the 15th century. He was tired of writing Chinese characters in Korean, so created a completely different writing system that was easier to learn and more adaptive to the Korean language. -__bean__-

"Ó o auê aí, ôu!"

In Portuguese....

"Ó o auê aí, ôu!" can be understood as "Hey, check out this messy situation that's going on over there". It's old slang but quite universal. Another meaning would be something along the lines of "Dude just stop, you're making a fool of yourself".

Edit: Brazilian Portuguese, that is. Enigmagico

Oh Danny Boy.

Irish people (particularly older generations) have their own version of English where they say sentences in an order that makes no sense grammatically but it makes perfect sense to any other Irish person. This is because the sentences are directly translated and word order is strange in Irish. Also as a result of this we say certain phrases that make no sense to anyone (I'm irish living abroad and I keep forgetting this).

Also just the fact there's 3 different ways to say the number two depending on context

A Dò (a doe) is if you're counting numbers as in one, two, three

Dhá (gaaww) is if you're counting things

Beirt (birch) is if you're counting people

Edit: There's a fourth way to say two

You use the word "dara" to say the second thing. The_Confession_Box