You’ve probably heard the story. When 16th-century Portuguese traders first landed in Japan, they would thank the locals with a polite “obrigado.” The Japanese, the story goes, heard this foreign word, liked the sound of it, and adapted it into their own language as “arigatō.” It’s a charming tale of cross-cultural exchange, one that seems to make perfect, intuitive sense. There’s just one problem: it’s completely wrong.
The striking resemblance between Japanese arigatō (ありがとう) and Portuguese obrigado is one of the most famous examples of a linguistic coincidence—a “false cognate” that tricks our pattern-seeking brains into seeing a connection where none exists. These are the echoes in the dark, chance resemblances that arise not from a shared history, but from the simple mathematics of human speech. So, let’s debunk the myth and explore why these fascinating coincidences are not just possible, but statistically inevitable.
The Case of the Deceptive “Thank You”
First, let’s put the arigatō/obrigado myth to rest. While it’s true that Portuguese missionaries and traders arrived in Japan in the mid-1500s, the word arigatō was already centuries old.
The term derives from the adjective arigatai (有り難い), a compound of ari (to have, to exist) and gatai (difficult). Together, it literally means “difficult to exist,” implying a sense of rarity and preciousness. A polite expression of gratitude, arigatō gozaimasu, can be thought of as, “This kindness you’ve shown is a rare and precious thing, and I am grateful for it”. This phrase appears in texts like the Man’yōshū, an anthology of Japanese poetry compiled in the 8th century—a full 800 years before the Portuguese set foot on Japanese soil.
Meanwhile, obrigado has a clear Latin root. It comes from the verb obrigar, from the Latin obligāre, meaning “to bind” or “to oblige”. When you say “obrigado”, you are literally saying “I am obliged”, expressing a social debt of gratitude.
The two words sound similar and mean similar things, but their histories are completely independent. So why does this happen? The answer lies in the fundamental building blocks of language.
The Math of Language: Why Coincidence is Guaranteed
Our brains are wired to find patterns. When we see two words from different languages that look and sound alike, we assume a link. But language operates on a surprisingly limited set of materials, making accidental overlap a mathematical certainty.
The Limited Phonemic Palette
Every language is built from a set of basic, distinct sounds called phonemes. Think of them as the atoms of speech. While the International Phonetic Alphabet (IPA) documents hundreds of possible sounds the human vocal tract can produce, no single language uses all of them. Most languages operate with a modest inventory of just 20 to 60 phonemes.
English, for example, has around 44 phonemes. Japanese has about 22. This small pool of available sounds is the first ingredient in our recipe for coincidence. It’s like having a limited box of Lego bricks. If thousands of people are all building small objects with the same 30 types of bricks, it’s inevitable that some of their creations will end up looking identical by pure chance.
The Constraints of Word Structure
Words aren’t just a random jumble of phonemes. Every language has rules, known as phonotactics, that govern how sounds can be combined. For example, in English, a word can’t start with the “ng” sound (like at the end of “sing”). In Japanese, syllables are almost always a consonant followed by a vowel (CV structure), like ka, shi, to, nu.
These rules dramatically narrow down the number of possible words, especially for short, common concepts. Core vocabulary words—like “water”, “hand”, “sun”, “bad”, or “dog”—tend to be short and simple across all languages. Given the limited phonemes and strict assembly rules, the number of possible one- or two-syllable words is finite. When you have thousands of languages all dipping into this same limited pool for their most basic words, overlaps are bound to happen.
A Gallery of Spectacular Coincidences
Once you start looking, you’ll find these false friends everywhere. They are a testament to the laws of probability playing out across the globe.
- English bad and Persian bad (بد): They sound identical and mean the exact same thing. Yet, there is no historical link. English “bad” has a mysterious and debated Germanic origin, while Persian “bad” comes from Middle Persian. It’s a one-in-a-million coincidence.
- English much and Spanish mucho: They look related, sound related, and mean the same thing. Surely they’re connected? Nope. English “much” comes from Old English myċel. Spanish “mucho” comes from the Latin word multum. They evolved on parallel tracks from two different Proto-Indo-European roots.
- Japanese namae (名前) and English name: Another uncanny resemblance in both sound and meaning. English “name” is an ancient word tracing back to the Proto-Indo-European root *h₁nómn̥. Japanese “namae” is a native Sino-Japanese word. Pure chance.
- English dog and Mbabaram dog: Perhaps the most famous example in linguistics circles is from Mbabaram, an extinct Aboriginal Australian language. In Mbabaram, the word for “dog” was… dog. There is absolutely no connection between the languages. It’s a perfect, beautiful coincidence.
How Linguists Spot a Fake
If coincidences are so common, how do historical linguists ever prove that two languages *are* related? They don’t rely on single-word resemblances. Instead, they use the comparative method to look for systematic sound correspondences.
A true relationship isn’t about one or two words lining up; it’s about a predictable, system-wide pattern of sound changes. For example, where Latin has a ‘p’ sound, its descendants in the Germanic family (like English) often have an ‘f’ sound.
- Latin pater → English father
- Latin piscis → English fish
- Latin ped- → English foot
This is Grimm’s Law, a regular, predictable pattern. Coincidences like bad/bad or arigatō/obrigado don’t fit into any larger system. They are isolated, random matches—linguistic ghosts with no history.
So the next time you hear a folk etymology about a word’s “obvious” origin, take it with a grain of salt. The real story is often less about romantic tales of ancient travelers and more about the elegant, predictable chaos of mathematics. The echoes you hear in the dark aren’t always voices from the past. Sometimes, they’re just the sound of probability, whispering across the vast and varied world of human language.