In the sentence
"She says she has no friends"
even though the number of friends is zero (less than two), why is "friends" still plural?
I learnt the rule that if a countable noun is two or more, it is written in the plural form. Therefore, the determiner "no" in this specific case really confuses me.
It's just that the normal expectation is she would have several friends.
We use the singular in contexts like He has no wife, or I have no car. We tend to use "do-support" or "got-support" anyway (He doesn't have a wife, I haven't got a car), so such assertions don't always sound completely natural regardless of the plurality.
Note that I have no son is likely to be bitter exaggeration from a father "disowning" his only son, whereas I have no sons is more likely if someone is lamenting the fact that he has no sons, whereas he would like to have several.
EDIT: (inspired by @DavidK's comment)
Suppose someone is standing in front of a "Beware of the dog!" sign. They'd probably say I see no dog or I don't see any dog in the singular, because they're only expecting to see one anyway.
But if they were on a country walk with a friend who'd just said There are hundreds of rabbits in these fields, they'd probably use the plural I see no rabbits or I don't see any rabbits.
It really is just contextual expectation that governs the plurality of "thing(s) whose existence is denied by the preceding word no".
The rule is not "two or more". The rule is "not equal to one". Zero takes a plural verb. "Zero books are on the shelf", NOT "Zero books is on the shelf." Likewise for words that mean zero, like "no" or "none". "None of the books are red", NOT "None of the books is red." "No dogs are here", NOT "No dogs is here". Etc.
You could say "She has no friends" or "She has no friend". Both are valid and it would be difficult to say if there is a difference in meaning between the two. That is, "no" can take either a singular or a plural noun. If you said, "She has zero friends", you must use the plural. You can't say, "She has zero friend". In the case of zero, the rule is, like for verbs, not "two or more" but "not one".
In English we use the basic form of a noun for a count of exactly one, and the plural form for every other number.
It's hard to say why that is - that's just the rule in English.
The rules are different in other languages. For instance in French zero is treated like one. The Unicode consortium, which promotes multi-lingual computing, has a nice comparison table showing the rules in many languages: Language Plural Rules.
It's intended as a reference for people making software, but may be interesting.
You mean "if a countable noun is two or more it is plural! We also usually use the plural with no.
She has no friends is the same as She doesn't have any friends. (Like the old song "Yes, we have no bananas".)
This Ngram shows that "...has no friend" was used more often in the past - but it is usually used when some description of the non-existent friend is added.
Poor Charles has no friend in the house.
He has no friend who is worthy of the name.
"No" in this context is a determiner, and has two similar, but slightly different, meanings. Sometimes it means "not a", in which case it takes the singular, just like "a" by itself, and sometimes it means "not any", in which case it (can) take the plural, just like "any" by itself. Note that there is no language that has a "nullary" number, as "zero" as a concept is actually quite recent, it was always "not a", or "not any", or "not (whatever determiner best suited the grammatical number of the noun in question)". As a result, nullary determiners ("no" in English) have variable number within languages, and the word for "zero" has variable number across languages (in English, it's plural, in French, it's singular).
Confusing? Yes. But then, so is the concept of nothing as something
Because English, as usual, is just unpredictable
For countables, "zero" uses plural. For uncountables, zero can use singular. That's why you have zero friends (you can have 2 - countable) and have zero interest in something (you can have some, or a lot - uncountable)
As is tradition in English, there are always exceptions. For example, both "zero interests" and "zero interest" exist, because they both refer to distinctly different concepts: former is a stake in a certain area (has nothing to do with desire for knowledge), latter is the want to know more (has nothing to do with loss or gain), then there's a different "zero interests" as in you have no desire to know about anything
Then there's ANOTHER kind of exception. If you're referring to a known subject, then you defer to that. For example, if you're out in the wilds and observe the distinct lack of dogs, you say "there are zero dogs", because you're talking about the concept of "dog" in general If you see a sign saying "beware of dog" and you notice the dog in question is not there, then you say "there is zero dog", because now you're talking about a specific dog, not just any dog
Normally however, you'd use "no dog(s)" because you're not trying to count, you're just observing the binary yes/no of the existence of a concept.
The rule two or more is not as correct as the rule not one. The rule should be "Add an 's' if the number of items is not (positive) one."
The following sentences are correct:
When we say a thing.. "a" denotes one as in singular.
Everything else, including zero, is plural.
If there isn't something signifying that it's a singular item then it's best to presume that it's plural.
An example that often trips up people is the difference between "people" and "person"... If we are talking about a single identifiable person or idea of a person then it's singular... If we are talking about many identifiable or countable individuals than it would be "persons"... And if it is a group of people that are not individually countable or identifiable then you would say "people"... If there are multiple groups of people that are separately identifiable then you would say something such as "both peoples"...
The indigenous people of North America and the indigenous people of South America to together combined to be "the peoples of North and South America".
It has to do with context. If it is part of a paragraph, and if in the conversation the topic is friends (plural), and a question is asked or the subject breached of her friends (plural), then the answer or sentence addressing the discussion should be within the same logic.
Example:
Bob has lots of friends. Jimmy has a few friends. But Lisa, I think that she says she has no friends.
friends. friends. friends.
"Bob has lots of friends," is a description of how many friends (plural).
"Jimmy has a few friends," is a description of how many friends (plural). The conversation is already about friends (plural), and in this description few could actually be one. But, to keep with the conversation, the plural version is used, and also because of the potential or more than one.
"But Lisa, I think that she says she has no friends," follows or is conversationally aligned inside of the paragraph with a description of how many friends (plural) that a person has. Having used two descriptions that include the plural "friends," has set a precedent of using the plural until the end of the paragraph. It could be set by one use, but for a stronger example you see here two.
It depends on the expectation. If I expect that you have zero or one, you would use the singular. If I expect that you have zero, one or more, you would use the plural.
I have no father. I have a father.
I have no mother. I have a mother.
I have no parents. I have one parent. I have two parents.
The normal expectation is to have one father, one mother, two parents. So you use "no" with singular for father or mother, and with plural for parents, and "a father", "a mother" vs. "one parent".
There may be two people you call "father", for example your mother's ex-husband and her current husband, or two gay parents. As long as that isn't expected by the person asking you, you would give the same answer, but of course the answer could be "two fathers". If I asked "was your father at the football game" and you have two people you call "father", you might answer "One of my fathers was at the game."
A situation where I expect several: "How many fathers and mothers were at the school meeting?" might have an answer "There were no fathers but seven mothers present". "No fathers" has the plural because it was likely that there were several.
In English counting "zero" values requires pluralization. Sometimes "no" means "zero", sometimes it is used as negation.
Counting is almost always valid, and negation is almost always valid, the one you choose to use depends on your intent and the context. Negation always preserves the plurality of the original statement.
If there is a question or implied question, it is usually best to use negation, which will never change the plurality of the question. For example, for the following statement:
You need a friend to enter.
A possible answer is:
I have no friend with me.
This is only because the question was singular and you are intended to negate it. If you responded with "I have no friends with me", it would be awkward, as it would mean you both pluralized and negated the original statement, where you should have only negated it.
Often times due to the ambiguity the use of "no" for "zero" is avoided, and can come across as a mistake. It is sometimes also used to emphasize certain words.
It will come across as more clear if you work around "no" for negation, such as:
I do not have a friend with me.
This makes it clear you want to negate the "friend with me" clause, instead of trying to count how many friends you have with you.
EDIT
I hoped I wouldn't have to get into the different between "form" and "meaning", as it is really convoluted, but I can't see a way to answer @gotube's comment with out. So... here we go.
Two sentences can have technically identical meaning, but different form. Often this is used for subtext (meaning not explicitly written, to imply politeness, intention, etc).
The best explanation of the differences between these I can think of, is using JavaScript (again, sorry for the complexity, but English doesn't do a great job at distinguishing these two, and I feel some English Language Learnings may know JavaScript):
// Negation
!people.some(person => isIsland(person)) === true
vs
// Counting
person.filter(person => isIsland(person)).length === 0
And so, "I have no friend with me", is not counting zero items, it is negation. The technical meaning (ignoring subtext) is identical to counting zero items. Mathematically speaking it is identical, which makes it confusing, but... it is just a different way to phrase it, and therefore, has different rules.
