I have the answer to a question that we've all asked. The question is, Why is it that the letter X represents the unknown? Now I know we learned that in math class, but now it's everywhere in the culture -- The X prize, the X-Files, Project X, TEDx. Where'd that come from?
Teño a resposta a unha pregunta que todos nos fixemos. A pregunta é: por que a letra X representa o descoñecido? Xa sei que iso é o que nos ensinaron na clase de matemáticas, pero agora está en todas partes na cultura: O premio X Prize, Expediente X, Proxecto X, TEDx. De onde vén iso?
About six years ago I decided that I would learn Arabic, which turns out to be a supremely logical language. To write a word or a phrase or a sentence in Arabic is like crafting an equation, because every part is extremely precise and carries a lot of information. That's one of the reasons so much of what we've come to think of as Western science and mathematics and engineering was really worked out in the first few centuries of the Common Era by the Persians and the Arabs and the Turks.
Fará cousa de seis anos decidín aprender árabe, que é unha lingua sumamente lóxica. Escribir unha palabra ou unha frase ou unha oración en árabe é como escribir una ecuación, porque cada parte é tremendamente precisa e leva consigo unha morea de información. Ese é un dos motivos polo que gran parte do que agora consideramos a ciencia, as matemáticas e a enxeñería occidentais en realidade foi concibido nos primeiros séculos da Era Común polos persas, os árabes e os turcos.
This includes the little system in Arabic called al-jebra. And al-jebr roughly translates to "the system for reconciling disparate parts." Al-jebr finally came into English as algebra. One example among many.
Isto inclúe un sistema en árabe chamado al-jebra. E al-jebr traducido quere dicir "o sistema para reconciliar partes dispares". Al-jebr introduciuse na nosa lingua como álxebra. Un exemplo entre moitos.
The Arabic texts containing this mathematical wisdom finally made their way to Europe -- which is to say Spain -- in the 11th and 12th centuries. And when they arrived there was tremendous interest in translating this wisdom into a European language.
Os textos árabes que contiñan esta sabiduría matemática por fin entraron en Europa, ou mellor dito, España, nos séculos XI e XII. E cando chegaron houbo un interés enorme en traducir esa sabiduría a unha lingua Europea.
But there were problems. One problem is there are some sounds in Arabic that just don't make it through a European voice box without lots of practice. Trust me on that one. Also, those very sounds tend not to be represented by the characters that are available in European languages.
Pero había certos problemas. Un problema é que hai certos sons en árabe que son imposibles para as cordas vocais europeas a non ser que se practiquen moito. Fiádevos do que vos digo. Ademais, eses sons tenden a non ser representados polos caracteres que están dispoñibles nas linguas europeas.
Here's one of the culprits. This is the letter sheen, and it makes the sound we think of as SH -- "sh." It's also the very first letter of the word shayun, which means "something" just like the the English word "something" -- some undefined, unknown thing.
Esta é unha das culpables. A letra SHeen, que soa como a nosa "xe" en "peixe" Tamén é a primeira letra da palabra shalan, que significa "algo" como na palabra inglesa "something", unha cousa indefinida e descoñecida.
Now in Arabic, we can make this definite by adding the definite article "al." So this is al-shayun -- the unknown thing. And this is a word that appears throughout early mathematics, such as this 10th-century derivation of roots.
En árabe podemos convertir isto en algo definido engadindo o artigo definido "al". Así que isto é al-shalan, a cousa descoñecida. E esta é unha palabra que aparece nas matemáticas antigas, coma nesta derivación de probas do século X.
The problem for the Medieval Spanish scholars who were tasked with translating this material is that the letter sheen and the word shayun can't be rendered into Spanish because Spanish doesn't have that SH, that "sh" sound. So by convention, they created a rule in which they borrowed the CK sound, "ck" sound, from the classical Greek in the form of the letter Kai.
O problema para os académicos medievais españois que tiñan que traducir este material é que a letra SHeen e a palabra shalan non se poden reproducir en español porque o español non ten ese SH, ese son do "xe". Así que acordaron crear unha regra pola cal tomaban prestado o son K, o da letra "q", do grego clásico na forma da letra khi.
Later when this material was translated into a common European language, which is to say Latin, they simply replaced the Greek Kai with the Latin X. And once that happened, once this material was in Latin, it formed the basis for mathematics textbooks for almost 600 years.
Máis tarde cando este material foi traducido a unha lingua europea común, é dicir, o latín, simplemente substituiron o Khi grego co X latino. E unha vez que aconteceu iso, en canto ese material estivo en latín pasou a ser a base dos libros de texto matemáticos durante case 600 anos.
But now we have the answer to our question. Why is it that X is the unknown? X is the unknown because you can't say "sh" in Spanish. (Laughter) And I thought that was worth sharing.
E agora temos a resposta á nosa pregunta. Por que o X representa o descoñecido? X é o descoñecido porque non se pode dicir "xe" en español. (Risas) E pensei que merecía a pena compartilo.
(Applause)
(Aplausos)