Travel, Teach, Live in Japan
One aspect of Japanese that confuses beginning students is the plethora of verb pairs. They seem to be everywhere, but unlike English, where you generally either have one word that works for both transitive and intransitive verbs (i.e., change, return, run, etc.), or else two completely different words (send back/go back; beat/win; raise/grow up, etc.), Japanese has pairs that sound almost exactly the same (modosu/modoru; kaesu/kaeru; mawasu/mawaru and so on). Furthermore, these pairs use the same base kanji, and only the ending of the word changes.
Before we get into how to distinguish between the two, however, let's make sure that we all understand what "transitive" and "intransitive" actually mean. Basically, a verb is transitive if it takes a direct object. Verbs like throw, set, and repair are all transitive, since they all take direct objects. It would be strange to say only "I threw", "She set" or "He repaired". All of these verbs require something else in order to sound complete in English. So: I threw the ball. She set the computer. He repaired the car. and so on.
Other verbs cannot take direct objects (or sometimes any object at all). These are intransitive verbs. Cry, sleep and sulk are examples. "I slept" is a perfectly good sentence in English, and even if you add something afterwards (a place, time, etc.), whatever you add will not be a direct object.
I slept on my bed.
I slept for ten hours.
I slept with my teddy bear.
You'll notice that in the examples immediately above, a preposition (on, for, with, etc.) comes between the verb and the object, which (in English) is how you know that it's an indirect object rather than a direct object.
If you're not into grammatical explanations, another way to think about it is this: transitive verbs directly affect the object of the sentence. Throwing a ball affects the ball in a very direct way; it changes the ball's location. On the other hand, sleeping doesn't really change the bed, the ten hours or the teddy bear. If the action directly affects the object, you can be sure that the verb is transitive.
So now that we've gotten that out of the way, what about those Japanese verb pairs? The first and easiest way to tell which of the pair is transitive is to look for a "su" in Japanese. If the verb has a "su" in it, it's a pretty good bet (actually a sure thing) that it will be the transitive member of the pair. And the verb without the "su" will be the intransitive one. This is one of the most consistent rules in Nihongo, so it pays to learn it.
Here is a basic list of some of the most common verb pairs you're likely to encounter. In each pair, the first one is transitive, the second intransitive.
Kaesu/kaeru (to return something, to return [oneself])
And so on.
The above is the easiest rule to apply for T/I verb pairs, an should be applied first, since whenever one of the verbs in the pair has a "su" that verb will be transitive 100% of the time. However, there are some other pairs that exist where neither verb has a "su". In this case, as a secondary rule, the best idea is to look for which of the verbs has an "e" in it, and that verb will usually be the transitive member of the pair. Some examples:
tateru/tatsu (Notice that this pair does not fall under the first rule, as what looks like a "su" in Roman letters is actually a "tsu" when written in Japanese.)
kaeru/kawaru (to change something/to be changed)
Although this second rule isn't quite at pervasive and all-encompassing as the first, it will still help you in the vast majority of cases.
So there you have it. Two rules that, when used in the correct order, will eliminate about 99% of the headaches you encounter relating to Japanese T/I verb pairs. The best thing about mastering this lesson is that once you get past the confusion, you can actually learn many Japanese verbs at twice the regular pace because you can just get both verbs in the pair at the same time. This is much easier than trying to memorize random pairs of verbs, or memorizing them one at a time.
If you are thinking about studying Japanese, Chris Chardon is the owner of Able Language Services http://www.able4language.com/en/, a successful language school located in Hiroshima, Japan. We have been in business since 1999, teaching all levels of students, many of whom have gone on to rewarding careers using the Japanese language.
A linguistics major in college, Chris himself spent a couple of years in traditional study before realizing that there are better ways. He rapidly became fluent enough to work as a translator/interpreter for a major Japanese company and do business in the language.