How do Koreans pronounced "iPhone 6"?

A normal person might attempt to answer this question by asking some Korean people. But we can take a less direct and more nerdy approach and try to puzzle it out.

First, some necessary background. (Stick with it, there's a payoff at the end.)

There are two sets of numbers in regular use in Korean. One set is the native Korean numbers that have been in the language for thousands of years. The native numbers from one to ten are:

1. hana
2. dul
3. set
4. net
5. daseot
6. yeoseot
7. ilgop
8. yeodeol
9. ahop
10. yeol

The other set is the so-called Sino-Korean numbers, which were borrowed from Chinese around 1500 years ago. They are:

1. il
2. i
3. sam
4. sa
5. o
6. yuk
7. chil
8. pal
9. gu
10. sip

Both are in common use, but usually only one set is used in a given context. For example, when telling time, the native Korean numbers are used for the hour and the Sino-Korean numbers are used for the minute. So "6:06" is:

yeoseot-si yuk-bun
'six-hour six-minute'

As in the example just given, whenever a Korean sees the written Arabic numeral "6", he or she will determine from context whether it represents native Korean yeoseot or Sino-Korean yuk.

6일 can only be yuk-il 'sixth day (of the month)'
6명 can only be yeoseot-myeong 'six people'

So that's the necessary background. Now we're ready to solve the mystery of "iPhone 6".

On a recent trip to Seoul, Erma and I noticed a billboard for the iPhone 6, visible from the train window just a few minutes outside of Seoul Station:

It's the square white billboard on the right. Click through to see a larger version of the picture. Or just look at the photo detail below.

Here's a close-up of the billboard, with the text transcribed in the caption to the photo:

"iPhone 6로 찍다"

The billboard says "Take photos with the iPhone 6". But how is that "6" pronounced? Erma and I wondered. Is it yeoseot or yuk? Neither of us are native speakers of Korean and we have no feel for what would be appropriate here.

But a moment's linguistic analysis yielded a surprising result: the answer is neither.

"iPhone 6" is followed by a Korean grammatical word, ro 로, which means 'with'. (Unlike English with, which as a preposition precedes a noun, this Korean word is a postposition which follows a noun.) The word ro is a bit like the English indefinite article a/an. The indefinite article has two forms: one precedes a consonant sound, and one precedes a vowel sound (e.g. a book, an apple). The Korean word also has two forms: ro follows a vowel and euro follows a consonant.

What this tells us is that "6" here represents a word that ends in a vowel. But neither yeoseot nor yuk ends in a vowel!

There's only one remaining possibility, and in Sherlockian fashion, we have no choice but to accept it. The word represented by "6" is the English word six.

"Oh-ho!" you say, Watson-like: "But six too ends in a consonant!"

"Quite so, my dear Mr. Watson. But you have overlooked one crucial fact. This is not the English word six as pronounced by Englishmen such as ourselves, but as pronounced in its borrowed form by people of Chosŏn."

That borrowed form is sikseu (pronounced something like sik-suh), which does indeed end in a vowel, and thus must be followed by ro, not euro.

So the answer to the question that forms the title of this post is: aipon sikeuseu. And we didn't have to ask any Koreans to figure it out!