Grammar

There's a lot to grammar, so I've divided up this page into smaller sections. Use the sidebar to navigate.

I'm using the same formality and gender codes from the vocabulary page here too.

Formality

How formal/respectful/polite your language is tends to be more important in Japanese than in English. Here are some formality indicators I sometimes use on this site to give a rough idea of where terms fit on the spectrum.

Very formal. The sort of thing you ought to use around deities, emperors, CEOs.... Because you have to choose words fairly carefully in these situations, I've only used this symbol with words that I'm almost positive are polite enough, and not when I'm only pretty sure. Whenever possible, I'm replacing this symbol with the next two, which are more precise.
Humble (modest), very formal. Use these words in very formal situations when referring to yourself (or your family, business, or other group of people you belong to, when talking to someone not from that group and thus effectively acting as a representative), to be appropriately modest.
Respectful (honorific), very formal. Use these words in very formal situations when referring to others (especially higher-ups and people you don't know well), to bestow honor and show respect.
Normal formal. This is what they generally teach you first in classes because you can use it in almost any situation. It's not excessively polite, but not likely to offend anyone either. It can work in casual situations as well, though it may sound rather stiff then.
Casual. The kind of thing that's likely to be used among friends, or when speaking to someone of lesser status (subordinates, children, etc.). Generally to be avoided in more formal situations, as it sounds a bit rude, but it's definitely preferable to....
Blatantly Rude. Avoid unless you want someone to get mad at you. I list words that are in this category because they do exist and because it's the kind of thing that's fairly common in anime.
Fairly formality-neutral. Implied when no symbol is used.
Unknown. These are words I've definitely seen or heard used, but I'm not sure how (im)polite they are.

The formality levels given are approximate. Different sources may list different or more levels, or classify some things differently. From what I can tell, there aren't really set levels of formality anyway; it's more of a continuous slope. It's just that some things are more polite than others and it depends on the situation which are appropriate. My symbols are merely intended to give a general idea of how formal or casual something is. Any question marks mean that I'm not so sure about it.

Gender

While there is, of course, nothing forcing people to choose words based on their gender, there are strong social tendencies and definite gender-based patterns in word choice, particularly in personal pronouns. A male using typically female language will sound strange at best, as will a female using male language (though perhaps less so). Where appropriate, words have been flagged with the following symbols:

Feminine, generally used by females. Often "cute" words.
Masculine, generally used by males. Often "rough" words.
Fairly gender-neutral. Implied when no symbol is used.
Unknown. These are words I've definitely seen or heard used, but I'm not about how they fit into this.

Again, these are tendencies rather than rules, so don't be shocked when there are exceptions. In particular, women are increasingly likely to use traditionally male words in recent years.

E-mail questions, comments, suggestions, corrections, etc.