Expressing time uses "時" (じ, e. hour) and "分" (ふん, e. minute). Note that the reading of "ふん" depends on the sound before it. See the time vocabulary page for a list of the possible readings.
Conversationally, the Japanese use 12-hour time. When it's not clear from context, "午前" (ごぜん) and "午後" (ごご) are used for before and after noon, respectively.
To ask for the time, use:
When "何" means "what", it's pronunciation is either "なに" or "なん", depending on what sound follows it.
When used to represent the hour of the day, the numbers, "four", "seven", and "nine" are pronounced differently from normal.
- ４時 (よじ)
- ７時 (しちじ)
- ９時 (くじ)
There are two ways of pronouncing "１０分"; "じっぷん" and "じゅっぷん". The former is taught as "correct" in school, but the latter is more common.
The pronunciation of "分" is "ふん" when it stands alone, but changes to "ぷん" in certain cases.