Basic Sentence Structure
Subject + Verb + Object
The order of a sentence in Japanese starts with the subject, then the object, and then the verb. This is quite different from English where the verb preceeds the object.
Most languages fit into either a Germanic or Latin base. French, Japanese, Italian, and Portuguese are more latin by origin. Japanese doesn't follow suit. It's unique in this way (only a handful of other languages can boast this attribute). Japanese doesn't follow the more common traits of grammar, it has some, but not many. This makes it one of the most difficult languages to learn or teach. So, as a student, cut yourself some slack.
Japanese use of prepositions ("on," "in," and "by") come after the nouns they are linked to in Japanese. We would say "in the ______" and the Japanese would say, "______ in".
Another difference you will notice in learning Japanese is that it is easier to express emotion, but harder to express time. Also, Japanese uses very few pronouns. This complicates how to determine who is doing what to whom, and makes the learning of Japanese a long-term affair.
Errors are common and are more likely to cause confusion than humor because of these grammatical differences. Again, don't get too discouraged. The more you engage in conversation, the more you will learn the ideosyncracies of this challenging language.
There are two levels of politeness you need to be concerned with. The third is not something you would concern yourself as a visitor or foreigner in Japan. The final verb forms in the first level are simple, they end in -masu or -desu (or -mashou or -deshou). Foreigners are not part of the "in-groupt" so this first level of polite language is almost always used.
The other level is an honorific language. It is used when speaking to people far above you- bosses, dignitaries, royalty. It may also be used with clients, elderly people, or to those you are treating with extreme respect. This level is subdivided into humble and exalted forms, if you are "lowering" yourself, or "raising" someone else. This is determined by your actions. Often, my actions are humbled, while their actions are exalted. This is a tricky affair as each verb has it's various politeness and honorific forms. Sometimes it is easier to find out what these are in conversation, instead of trying to make the verbs work on your own.
Commands, being verbs, have their politeness levels that are carefully used. You don't want to sound too abrupt or rude when issuing a command. These differences should be learned so that you can make commands (requests) of superiors, and cheer on your favorite sports team. For example, Suware (don't use this on its own).
To be casual use: Suwari nasai
A more polite way: Suwatte kudasai
The Honorific: Osuwari kudasai
All of these can be taken to mean, "Sit down" or "Please sit down." You just need to know when to use them. Also, there are other forms to consider:
Suwaranakute wa ikemasen. = "You must sit down."
Suwatte wa ikemasen. = "You must not sit."
Suwaranaide kudasai. = "Please don't sit."
Japanese is an indirect language. "Speaking your mind", as we often do in the West, is considered rude or uncultured in Japanese. If you are subtle in just the right way you will master the real art of Japanese communication. The Japanese language will take conversation in such a way, without being obvious about it, so that the person
being talked to feels comfortable and honored. This doesn't mean that Japanese is indecisive or lacks precision. On the contrary, Japanese is probably too precise for us (Westerners) to understand all of its subtleties.