Most classes that teach Japanese teach the formal, polite type of Japanese. This is because it's always good to be polite. It's OK to speak politely to people you know casually, but it might not be OK to speak casually to people you're supposed to be polite to. The only problem with this, is that people in anime or the streets of Tokyo are often speaking the casual form of Japanese. For example, in our last lesson, when we were talking about shopping I mentioned that if the shop didn't have something you asked for, they might say "Arimasen"= "Doesn't have it", but they might also say "Nai des'" or even just "Nai", which is less formal than "Arimas'" or "Arimasen". "Nai" is used with a verb (and sometimes just by itself if the verb is already understood) to mean "Not" or "Isn't".It might take you a long time to learn to say all of the different formal and informal forms of Japanese verbs, but you can at least learn to understand them when you hear them. For example, you've learned the formal way to say "Understand" in Japanese: "Wakarimas'".
| Present Tense | Present Negative Tense | Past Tense | Past Negative Tense |
| Understand | Doesn't understand | Was understood | Wasn't understood |
| Wakarimas' | Wakarimasen | Wakarimashita | Wakarimasen deshita |
| INFORMAL | |||
| Wakaru | Wakara nai | Wakata | Wakara na kata |
Complicated? A little, but look at what they all have in common: the "Waka-". If you know that, you should be able to "Wakaru". Verbs ending with the formal "-mas'" (masu) are all shortened in this way for informal speaking. "Ikimas'" = "to go" can be shortened to "Iku". When being formal, you can invite someone to go with you with the word "Ikimasho", but if you are being casual with your friends, you could shorten it to "Iko". You can order someone to go with "Ike!" (Ee-keh). You hear this one in anime a lot, like when Karamaru orders his Kara-kara Ninja to attack, or in one of the many fighting monster shows where a trainer sends out his or her Pokemon/Digimon/Monster thingie. I'm not sure if there is a formal way to order someone to do something, if there is, no one really uses it anyway.
Aside from verbs, informal Japanese also shortens "Des'"(desu) to "da". "Kono piza okii da." = "That pizza is big." And, sometimes you can ask questions without the "ka?" at the end, just by the inflection of your voice. You learned how to ask "What is this?" in Japanese as "Kore wa nan des' ka?", but in informal speech, you might hear "Nani kore?", or "Nan da?".
Since most Japanese shows use a lot of this informal style of speaking, knowing a little about it will help you get more out of watching Japanese anime and movies. Most of the difference between the styles is in the endings, so if you know the base part of the word at the beginning, you should be able to figure out the meaning.