Verb to Noun
First of all, sorry for the lack of Hebrew. It's hard to find computers with Hebrew in China and you usually can't install it without the CD (unlike in Thailand, where installing Thai installs whatever Hebrew requires). The regularity of changing verbs into nouns (what you'd call in hebrew "שם הפעולה") is quite straightforward. You should know the major verb groups though: 1. Ichidan (always ending with either 'iru' or 'eru', but not every verb that ends with iru/eru is Ichidan). 2. Godan - virtually all other verbs. 2a. Godan-aru - very few Godan verbs, most if not all of them are extremely polite like gozaru and irassharu. Don't worry about them too much - they're rarely used in this case. 3. Irregular verbs - just 2 of them, so it's not a big deal. There are also some other ancient and mostly extinct group like Nidan which you don't have to pay attention to, unless you want to study classical Japanese. For each of the groups, you do this: 1. Ichidan: take off the ending 'ru' (that's the starting point for almost everything you'd ever do with Ichidan verbs, and here it's the only thing you need to do): taberu -> tabe 2. Godan: Change the 'u' at the end to 'i'. hiraku -> hiraki, akaru -> akari. 2a. Godan-aru: Replace the ending 'ru' with 'i'. irassharu, irasshai. This is also the command-form for those verbs. 3. suru -> shi. About kuru I'm actually not quite sure... I think it should be ki, but I might be wrong. This 'noun' form, is also the stem form, which you use to add several suffixes like the formal masu (except for kuru, in case I'm really wrong). You should also keep in mind that this form is not always the name of the action. This form is used as a stem (like I mentioned before), in compound verbs and in lyrical language for an action that's followed by another (what you'd use te-form for in everyday language). The very example you gave (oyogu -> oyogi) is quite wrong. Although they may understand your meaning, the Japanese would say suiei most of the time, for swimming. (I don't have Japanese, so I'll try to approximate in Chinese: 水泳)