DEAR MISS MANNERS: My 15-year-old son is hearing-impaired and wears hearing aids, which are, by design, hard to see. He is very polite when he asks people to repeat themselves when he cannot hear them, and he explains he is hearing-impaired.

A couple of times, people have questioned this. One time he was chastised for "joking," and I finally had to step in and say, as nicely as possible, that he is, in fact, hearing-impaired and has been since he was 2.

Just recently he was getting a haircut and had given his hearing aids to me to hold, and the stylist chastised him when he asked her to repeat herself. She said hearing impairment was not something to joke about -- and I again had to step in.

My son is getting older and I am not with him all the time. I am not sure what to tell him to say to people without sounding rude or having to take his hearing aids out to show them as proof, which I do not feel is appropriate or necessary. Although he finds it annoying, he expects people to react that way sometimes.

GENTLE READER: Your son needs to master a two-step response. In step one, he re-explains the situation with convincing seriousness but without rancor. Waving around medical devices of any kind at this stage might be effective, but is certainly not dignified. Mentioning the fact that it has been this way since he was 2 should be convincing.

He should then pause while the information sinks in. Only when the listener realizes what she has done is it time for step two: assuring her that he understands her mistake, as the disability is not obvious.

Miss Manners is sorry to say that it is likely your son will have many opportunities to practice.

DEAR MISS MANNERS: If you have a guest in your home and you overhear a negative comment, how are you to react for the duration of the guest's stay?

GENTLE READER: That will depend upon the nature of the comment.

Miss Manners recommends pretending not to hear the ungenerous comment about the salmon, as it was not intended to be overheard. The unmistakably uncivil comment to, or about, the hostess, however, will require a period of frosty politeness of length in proportion to the severity of the rudeness.

DEAR MISS MANNERS: A friend of mine invited me to a (friendship, not date) social outing. I said I would go, but he didn't tell me until the last minute that it was also a singles group. I completely disagree with singles groups, but I agreed to go before he told me that.

What's your thought about people not disclosing all the information about a social event when inviting someone, and would it be rude for me to now say I don't want to go?

GENTLE READER: Insistent as is Miss Manners that invitations, once accepted, must be honored, the rule is not absolute. If the bride changes the date -- whether due to uncertainly about the catering or the groom -- guests are also given an opportunity to re-evaluate. Miss Manners extends the same exemption to your situation.

(Please send your questions to Miss Manners at her website, www.missmanners.com; to her email, dearmissmanners@gmail.com; or through postal mail to Miss Manners, Universal Uclick, 1130 Walnut St., Kansas City, MO 64106.)

DEAR MISS MANNERS: I was just wondering why the blade of a knife faces in toward the plate and not out?

GENTLE READER: Throughout the noble history of etiquette, there has been concern, to the point of alarm, about the possible misuse of table knives.

It was bad enough that for centuries before the widespread adoption of the fork, people used to spear their food on the tips and introduce the knife into the mouth. But they might also be tempted to use knives for murder or, worse, picking their teeth.

Thus there have been various rules passed in an effort to tame such instruments, such as blunting the tips (a French 17th-century dictum) and turning the sharp part in. If you have never been attacked by a dinner partner, Miss Manners trusts that you will see the wisdom of this.

DEAR MISS MANNERS: My husband's cousin has just sent out the third save-the-date card in the last four years. The last time was for a destination wedding. This time it is for a winter wedding.

Each time, the family does showers or donates money to help out. But there are never any weddings or any discussions about broken engagements, or any gifts or money returned.

Am I obliged to help out or attend yet another pre-"wedding" money grab? How can I extricate myself politely?

GENTLE READER: What an interesting scheme these people have invented. Please reassure Miss Manners that you are not on the verge of falling for it a third time. The adage "Fool me once, shame on you; fool me twice, shame on me" comes to mind.

In any case, even under the best of circumstances, a save-the-date notice does not require any response. It is merely a courtesy to those who want to plan ahead, and is neither an announcement nor an invitation, although those who sent them are obliged to follow up with invitations when the time approaches.

DEAR MISS MANNERS: I am going to host Thanksgiving dinner for the first time for my own family and in-laws. My brother-in-law's daughters' birthdays are in November, and he wants to have a small birthday moment for the girls at the Thanksgiving dinner.

I don't feel like mixing Thanksgiving dinner with the birthdays of their kids. What should I do? I don't want to upset them.

GENTLE READER: Why not? You've already upset Miss Manners.

Evidently, you are not thankful for these little girls. But beyond that, you are so far ignorant of the spirit of the occasion as to imagine that there is some way to avoid horrifying your in-laws if you act on your indifference to your nieces.

DEAR MISS MANNERS: I have received a birth announcement from my cousin's daughter saying they are "looking forward" to our seeing their new twins. However, there is no invitation to any viewing event.

GENTLE READER: Infants, like royalty, do not run about socially, but expect people to come to them to pay obeisance. You have been encouraged to pay such a call, although Miss Manners trusts that you will first check that it is at the family's convenience.

(Please send your questions to Miss Manners at her website, www.missmanners.com; to her email, dearmissmanners@gmail.com; or through postal mail to Miss Manners, Universal Uclick, 1130 Walnut St., Kansas City, MO 64106.)

DEAR MISS MANNERS: My email complaint: selective response rates!

If you frequently exchange emails with another person and begin to realize they respond quickly to what is important to them and take forever if it is not -- i.e., it is important only to the sender -- it is offensive and inconsiderate.

GENTLE READER: It seems to Miss Manners that we already had an instrument that interrupted others and demanded that they give us their attention this instant.

That was what the telephone did before we realized how annoying it was and built in some protection, or even stopped using it. Please do not attempt to impose this demand on a convenient way of getting to people quickly without compromising their ability to sort their messages for degrees of urgency.

DEAR MISS MANNERS: This year my adult children are refusing to attend Thanksgiving or Christmas dinners because my dear cousin, who always hosts, doesn't start cooking until we have arrived.

This means about two or three hours of snacking, drinking cocktails and making conversation before dinner is served. She always provides delicious hors d'oeuvres and wines, but by the time dinner is ready, we are all ready to go home.

My cousin takes great pride in hosting these meals, and after 50 years of eating Thanksgiving turkey together, I really don't want to hurt her feelings. We could all come up with various excuses not to come ... frail elderly mother, new baby, and so forth. Somehow I think we would all be losers by doing this, losing the pleasure of being together with family and hurting my cousin's feelings.

I hope you can help me find a way to talk to her about the problem, and let her know that her approach to hosting is driving all of us away. It seems like she will get her feelings hurt no matter what I do, but I have to do something, because my daughters and their partners are going to be so very obviously absent.

GENTLE READER: Instead of using elderly mothers and new babies as excuses not to come, you might use them instead as excuses to help set time limits. Tell your cousin that you all love coming to her house for the holidays, but that unfortunately it is too much for some family members to make it an all-day event. (Maybe the first time after saying so, offer to come early to help with the preparations and invite the others for a little later. Then you can have a firm hand and eye on the timing.)

Miss Manners sympathizes with your plight and commends your patience not only with your time, but also with your digestive system. It is not easy to eat and drink for three hours before finally sitting down to eat and drink.

It may just be that your cousin enjoys the extra time spent with family on these occasions. If you show that you enjoy it too, but also want to be respectful of others' time, she will likely be much more amenable to your concerns.

(Please send your questions to Miss Manners at her website, www.missmanners.com; to her email, dearmissmanners@gmail.com; or through postal mail to Miss Manners, Universal Uclick, 1130 Walnut St., Kansas City, MO 64106.)