It is true that this question shows no research and it would be appropriate to close it were it posted by an adult. But the OP is in the sixth grade! Should we not cultivate this budding linguist instead of dismissing her/him?
Possibly this is a homework question, but I'd give someone with the user name of mathlete the benefit of the doubt.
Children who want to participate in activities with adults should be expected to play by the same rules, unless the rules make it impossible for them to participate (usually that only happens for physical activities though).
We should be helping all new members learn how the site works and what the expectations are, and we should be doing it in a kind way, so I don't see any reason why children would need to be treated differently. If you are being harsher to a new user than you would if you knew they were a child, maybe you should be kinder.
On ELL we often will try to help a new user get their question up to standards without immediately closing it, but once the help has been given and the user has some experience with the process, our expectations go up. Often, people live up or down to what's expected of them.
First, generally speaking, sixth grade is too young for membership without special parental consent, unless the member has been held back. Compulsory education starts in kindergarden at age 5, and should be counted grade 0, then increment the grade by one for each passing year. Being in sixth grade means you have been in school for 7 years, and 5+7 is 12.
Our terms of service require members to be at least 13 years old to join. The reason this is done is to comply with the Children's Online Privacy Protection Act, which forbids websites from collecting any information from people any younger without written parental consent. Now it is possible that C.O.P.P.A. violates the first amendment of the U.S. constitution, but I do not think the Stack Exchange network is willing to risk putting itself into a position where it has to contest that point in a court of law. We may need to suspend this person for a year, if not only for legal reasons. Since tchrist saw that post and it is his job as a moderator to act as a liaison for corporate, he should probably consult upper management to verify whether or not this member has the requisite parental consent to even be among us.
Second of all, wanting to educate schoolchildren is a noble goal, but it is not precisely our goal, and we should not lower our standards to accomodate people outside of our intended user-base, 'lest we want to risk losing our focus. Part of the reason we have this rule is to keep our list of incoming questions relatively clear of frivolous content which is of no interest to our expert linguists, etymologists and English language enthusiasts. I see no more reason to favor sixth graders than we do E.S.L. learners, and as a matter of fact, there is even less reason to do so since somebody in grade school should have a tax-funded schoolteacher aiding them with their education, which is a luxury that some impoverished E.S.L. learners may not have. Also may be possible that this person should probably be redirected to E.L.L., keeping in mind that the reason it had its name changed from E.S.L. was to be at least somewhat inclusive of native speakers, based on what I read in the Area 51 proposal.
Thirdly, lowering our standards for children may be underestimating their abilities. Young people start learning how to use computers as young as age 3 these days, and by the time you're 12 you should be expected to have some amount of proficiency in using them. Young people often have better grasp of basic computer knowledge than adults. I believe it is reasonable to expect that twelve year olds surfing the web and asking a question like that should be able to devise search terms to the effect of list of words plural words that end in i and find the wiktionary page just as well as anybody else. Now normally, I wouldn't consider wiktionary Gen. Ref., but Wikipedians are very good at making lists, and I have no reason to believe we can do any better than they do. Even if we can, perhaps that effort would probably be better spent improving the Wiktionary list, especially since this question is too broad for the S.E. format anyway and it may be seen by more people.
Fourthly, part of the goal of our research standard is to prevent impractically redundant questions from being asked. Maybe somebody should link this child to the Wiktionary list in a comment, but unless we can do better then we're just making the internet harder to navigate by needlessly competing with it.
Finally, identifying people by age is very difficult, especially since the S.E. corporation is prohibited from doing so without user consent by the terms of the privacy agreement. What's to stop me from claiming I'm in third grade, and not researching any of my questions if the sixth grader can get away with it?
Anyway, don't get me wrong. If a precocious young child who has the requisite permissions wants to be a member of our website, I think that would be great, but only if he or she plays by the same rules as the rest of us, and we should use comments to guide such users into improving their questions in the same manner as we would any other user, so that they may learn to ask questions properly.
To quote Jay Hanlon in War of the Closes:
The goal was always for some closures to drive an edit, improve, re-open cycle. The user gets helped, gets better at asking, and the community gets useful content.
