A friend pointed out to me (indirectly) that it’s actually not entirely obvious how to be a good ally to a plural system. There are some really obvious questions with not so obvious answers, like when or whether you should talk about it, where to find resources for education, and so on.
The first thing I want to say is that it’s good (just like with being a trans ally) to let them self-determine: ask them how they’d like to be referred to – pronouns, names, etc. And when they’d like to be referred to. It’s a similar sort of dynamic to the trans thing there, too – among some friend groups it’s okay to refer to them plurally and by name, among some friend groups it’s probably not. The simplest thing on this is just to follow their lead. If you hear them talk about themselves openly, then it’s probably okay to discuss it openly.
Some people are very private about themselves, but there’s a good chance that if they’ve made their presence known to you, they’re okay with you asking questions and being curious, as long as you’re respectful. (See the page about the bad kinds of questions.) I can’t speak for every plural system, but for us, we are super happy to hear that someone is interested and wants to know more.
Please be aware that if you ask to hang out with someone who’s not in front, you’re also asking for the person who is to leave. Some people are bothered by this, and others are not. It’s a good thing to ask if you find yourself wanting to ask for specific people. “Is it okay to ask if I can hang out with ___?” With us, for example, we have no problem with this as long as there’s a reason (X is Y’s friend). Some do, though. It’s also worth being aware, on this same topic area, that many plural systems can form headaches or mental fatigue from too much switching, so keep that in mind when asking. All of this tends to be less of an issue online, where most plural systems can (with some effort) multitask and appear as separate people.
Different people have different theories about how plurality works and why it exists (including you, probably). However, it’s important to respect your friends’ beliefs here, even if you don’t believe them too. If they say they are totally separate people and not fragments of a person, that’s what their subjective experience is. If they say they came from another world and only visit here, again, that’s what their subjective experience is. It’s the same as with any religious or spiritual belief system: you don’t have to believe it yourself, and it harms no one to let people respectfully hold their beliefs.
As far as education – I hope that anyone would find this web site itself to be a positive educational resource. In addition to what’s here, you can also check our links page for insight from other systems. There’s a lot of diversity out there, in types of systems, origin beliefs, whatever. I’d encourage people to take a look if they’re interested!
If you are interested in going further, then you could respectfully take a moment to correct people who are spreading untruths about plurality, in other contexts. You’ll have to determine if it’s safe to say “I knew somebody once” (i.e. don’t do this if it will out your friends), but in any case, if someone says something like “yeah, that movie with the multiple personalities was scary because they’ve always got a violent person” then you could correct them and say that no, not all plural groups have violent members (in fact, most do not), and that they are not just personalities, but people. Who knows, you might get someone interested in the truth.
I’ll be updating this document further as I get feedback.