Roger Woodham replies:either, neither and too

Either indicates a choice between two alternatives. Neither combines two negative ideas. Study the following examples of use:

• Which of these apples would you prefer? ~ I don't want either of them, thanks.
• You can have either the ?cotton top or the ?cotton-and-polyester blouse. You can't have both.
• Neither Richard nor Judy could come to the party.
• I want neither alcohol nor cigars for my birthday. Now that I'm fifty I must live a healthier life.

Both either and neither can function as pronouns, determiners or adverbs.

When they function as pronouns, they are often followed by of + noun phrase:

• I've known you for two years, but I haven't met either of your two brothers yet. (OR: I've known you for two years, but I haven't met either Francis or Damien yet.)

• Neither of my two brothers survived the war. Neither Francis, nor Damien.
• Which of these fur coats is yours? ~ Neither (of them). That one's mine.

When they function as adverbs, they behave as linking words which can be tagged on in agreement at the end of a negative sentence. But with neither, subject and verb are inverted, with either this does not happen:

• I can't make the meeting on Tuesday. ~ No, neither can I (OR: No, nor can I.)
• I can't make the meeting on Tuesday. ~ No, I can't either.
• I don't approve of sex before marriage. ~ No, neither do I. (OR: No, nor do I.)
• I don't approve of sex before marriage. ~ No, I don't either.
• I don't go mountain climbing and I don't go mountain walking, either. (OR: I don't go mountain climbing and neither do I go mountain walking.

Too can function as an adding adverb which is placed in agreement at the end of an affirmative sentence. Compare the following:

• I like peaches and nectarines best. ~ Yeah, I like peaches and nectarines, too.
• I don't like peaches or nectarines. ~ No, I don't like peaches or nectarines, either.

When either and neither function as determiners, they are placed before the noun.

• On neither side of the road was there anybody to be seen.
• Neither player could raise his game. It was a very boring game of tennis to watch.
• The sisters in the photograph were standing on either side of their dad. (OR: ...on each side..., OR: ...on both sides....)

Neither of them is or neither of them are?

I don't think there is a clear answer, Wojciech. Although this of-pronoun is normally considered singular, it is normally followed by plural nouns or pronouns. Thus, the boundary between singular and plural is blurred and effectively it can go with either a singular or plural verb form. Strictly speaking, it should be singular, but you will hear both formulations with no clear preference for one or the other:

• Neither of them are coming. They both have to work next weekend.
• Neither of them is coming. They both have to work next weekend.
• Which of these umbrellas is yours? ~ Neither of them are. That one's mine.
• Which of these umbrellas is yours? ~ Neither is. That's mine.

There is similar confusion, I think, when neither...nor are employed as conjunctions, meaning not one and not the other. Consider the following:

• Neither Francoise nor Helmut likes to eat English breakfasts, even at weekends.
• Neither Franciose nor Helmut like to eat English breakfasts, even at weekends
• Neither Emma nor Susan gets on with Chloe.
• Neither Emma nor Susan get on with Chloe.