I've been studying Japanese for a while and whenever I tell people about it, I like to point out that a lot of words in common use and written on signs and billboards is actually English. Kind of.
In written Japanese there are three character sets used. Each has a specific purpose, but all are used together in sentences. The first is Kanji. These are characters borrowed from Chinese and represent a meaning rather than a sound and there are literally thousands of these (you need to know about 2,000 kanji to read a newspaper). One kanji can have multiple different pronunciations and can mean different things when combined with other kanji. It looks like this:
This is how Shinkansen or "bullet train" is written. If you broke down the meanings, the first kanji means 'new', the second means 'trunk' and the last means 'line'. So its the new main train line.
The second character set is Hiragana. Hiragana is phonetic and has only 46 characters. Unlike Chinese, not every Japanese word has a meaning based character. Some, like English, are always sounded out using Hiragana or use a combination of kanji and hiragana. Additionally, anything written in Kanji can be rewritten phonetically in hiragana. Here's shinkansen again:
Some public signs might be written this way to make sure important information isn't limited to just those with a good kanji vocabulary.
The final character set is katakana. Katakana has a dual purpose; onomatopoeia and foreign words. It may sound like a strange pairing at first, but it makes sense since on the surface, a word in a foreign language is just another meaningless sound like 'meow' or 'tick-tock'. Katakana has exactly the same number of characters as hiragana. In fact, there is a 1-to-1 mapping. They look somewhat similar, but katakana is meant to be faster to write. Think of the difference between cursive and non-cursive writing in English. It would never be written this way, but here is shinkansen in katakana:
シンカンセン
This is where Japanese can become interesting, especially if you're just learning. There are a lot of borrowed English words in Japanese. Since they are all written in katakana, if you can learn these few 46 characters, you will be able to get the gist of a lot of signage around Japan.
There is a slight problem however. The first problem is that there is not a 1-to-1 mapping between Japanese phonetics and English phonetics. Japanese does not have clustered consonants (except for a few cases). Japanese phonetics are a combination of a consonant and a vowel. So, while a sign written in katakana may represent an English word, you must invoke your inner Cookie Monster and sound it out in your head. You might see:
ドーナツ
Which translates phonetically to dou-na-tsu, or donuts. Now you say, "Score! I found donuts!" However, while there are a lot of English words in use in Japanese, a lot of them have been chopped up, rearranged or perverted in some way, making them almost unrecognizable.
One example is "cosplay" or "costume play" or basically "dress up." While many people may already know 'cosplay', there are many lessor known (to non-Japanese) word combinations that would escape recognition if the katakana was sounded out. They're like the inside joke that you don't get without additional context.
Recently, this secret-life-of-English-in-Japanese turned a mistake I made in Japanese into big laughs. I was having an IM conversation with a friend about the current rainy season in Japan. She taught me that the word for the cheap plastic umbrellas they sell in the subway for $2 is 'binigasa.' I mistakenly wrote it back to her as 'binigasu.' The 'bini' part is actually short for 'conbini' which is short for the English "convenience store." The 'gasa' part means 'umbrella', but changing 'sa' to 'su' makes it look like my name, phonetically spelled out in Japanese, Gasu.
So, Japanese is full of English words that can make it easier for a first time traveler to get around. But, as I've often found, it is equally easy to make a room full of Japanese laugh while, attempting to speak in what you thought was English, you explain how you bought a convience store version of yourself in the subway.
