I gave one answer already, but after coming back to this a few months later, I have some other ideas that constitute a separate kind of answer.
The summary is this: keep it practical, memorable, and fun. Don't make it annoying, frustrating, confusing or difficult
Here are my thoughts on what that means and how that works, in depth...
Naming schemes = fun, practical, and accessible
- Names are one place you can have a lot of consistency/creativity/fun:
- They CAN consistently appear in a story, and sound unique to a culture/civilization.
- Then naturally add cultural/species flavor/reference without having to be overt or go out of your way.
- Live events (the CON part of the OP question): Name guidelines might be a good way to make it easy
- easy for amateurs to participate without much effort
- easy for RPG characters or shared storylines.
- Easy to prepare just once
- Requires minimal practice after coming up with a name.
- Rule sets need not be memorized, only referenced.
Creating a "sound" for a language and its names.
You probably want a practical, pronounceable, memorable and identifiable set of sounds, so people can say the equivalent of "that sounds like Klingon!" or "Is that a southern accent?"
Start with a subset of English vowels and consonants (there are about 40 phonemes if I recall, with regional variations)
- WHY create a sub-set of English sounds:
- Pronounceable and thus memorable to readers
- Won't slow English readers/audience down or frustrate/annoy.
- Lets readers/audience just enjoy it without trying to remember stuff
- eg, that "#" means "purring chitter sound"
- eg, prevents second-guessing or stopping to check the book reference (and ruining plot flow or event participation).
If you really want something unique/unpronounceable... go ahead, but follow these
- If you're passionate about coming up with something unique that humans can't pronounce or remember... that's fine, but...
* Come up with easy English equivalents for any repeated use/reference in written form.
* Have some exposition or conversation about why-this-nickname (because the characters want to reduce pain for the same reasons as the readers).
* Think about how names get slaughtered and translated to equivalents in reality. It's a practical necessity. I will learn to respond to a Spanish pronunciation of my name when I'm around spanish-native speakers.
- To demonstrate by example... Try to read/memorize "Xt'grktm" versus a pronounceable version "Zet-griktam", or "Łßňĵ#" vs "Luhss-nuhjay-(chitter)".
Define some nonverbal language, and use non-English/nonhuman sounds like body language.
Restrict unique sounds to nonverbal cues and filler words --
Allows you to use these traits to add flavor/tone but not direct meaning
Nonverbal cues have several advantages:
- Don't need to be remembered, consistent, looked up in a reference, or constantly explained.
- Need not be pervasive. You don't have to over-describe or over-use it, because it's not intrinsic to the langauge.
Non-verbal and non-auditory cues.
For con participants, these are probably easier to adopt and sprinkle into interactions, and don't have to be as consistent.
For readers, this can be a good way to sprinkle in some sense of alien/difference without overdoing it
Simple sounds: purr, growl, chitter, whistle, clicking, rasp, rattle
Variations add flavor: soft purr, low growl, high-pitched chitter
Remember to add variations/combinations to the unique sounds.
Combinations add flavor/complexity later on: growling chitter, singsong purr, rasping whistle, rattle-growl, etc.
Invert/change the meaning: Just like the real world, nonverbal cues can be misjudged or misunderstood, like how the thumbs up is like a middle finger in certain countries, or pointing can be done with chin/lips, index finger, or the whole hand (and each can be offensive/quirky in the wrong countries)
- e.g. a purr actually indicates anger/negativity in a feline species, and it makes frustrating situations worse between them and humans.
- Only use this in long-form fiction where you can establish the context, and maybe even use it as a plot device for/against protagonist/antagonist/others.
Language and culture are linked, and are never homogenous
- Remember: Language, culture, and nonverbal cues are all linked.
- Avoid "planet of the hats" or having a single rule set
- Make sure to identify one or two variants of language/pronunciation
- These variations come from sub-cultures, continents, dialects, sub-species, or alternate belief systems for a race/world.
- Don't overdo it--it should give variety but still be memorable and fun, allowing audience to easily remember the implications rather than giving them a burden of remembering/reminding/frustrating details.
- If names are going to be part of the dialogue, or at all important, simply having those names appear may be enough reminder of language differences.
HOW to select a subset of English sounds - some ideas
You can be arbitrary--just pick a consonant or sound and strike it out. Not everything needs a reason.
Also be logical. Think about biology, morphology, nutrition, and cultural influences on language and tone
- IE, decide that the vowel sounds "O/oo/ou/w" are difficult for
feline inexperienced speakers (requires lip shapes that muzzles don't have).
Don't be absolutist - think about variation & difficulty
- Decide which English sounds are hard
- Do not exclude these sounds entirely--but soften the sounds and reduce their frequency based on how difficult they are.
- e.g. muzzle mouthed: any labial and dental sounds are hard, but not impossible
- Remember that most sounds can be imitated very closely in alternate ways. The dental sound "t" is hard for canine/muzzles, but easy enough to move to the tongue & palette -- sounding closer to a "d" but not alike. This is easy enough, in fact, I wouldn't even exclude it from the language.
Be logical about skill variations (fictional character skill and participant skills)
- Characters/actors with less actual skill/practice can be the "more experienced English speakers" without worrying about messing up too much.
Come up with some common names or naming patterns from sub-cultures/tribes/backgrounds. In English, you have O'hare/O'donnell, Robinson/Anderson, Swensen/Jensen. In Hawaiian, they have the glottal stop (heard in uh-uh and noted by apostrophe in Hawai'i); many pacific island languages have far fewer consonants because of dietary/malnourishment over generations - reducing dental sounds mostly.
Decide how names are constructed and used. Do people go mostly by surname, tribe? Are there common endings for male/female or other identifying morphological/familial traits? Avoid having a single answer for any of these.
Muzzles, specific examples/ideas:
- If the muzzle-mouthed crowd are mostly from normal human cultures or heavily influenced by them, this should give less weight to any pronunciation differences--focus on softening or slightly altering some vowels and consonants. This is also easier on reader/actor/audience, and gives an out/explanation for those whose pronunciation is more English.
- For casual actors/participants, find simple rules. IE, say everything while making a 😬 grimacing/smiling/toothy mouth shape with cheeks stretched & frozen. It's much easier than learning any complex rules.
- Experiment with talking without moving your lips much. Identify which vowels and consonants come out differently or not at all. Try to imagine how they might compensate if required to do so (you can make most sounds using other means, or close enough). Note which ones require more effort and practice. For example, if you have sharp teeth, "th" might have to be produced using the soft palette--it can be done, but it sounds slightly off. Think about how ventriloquists sound (especially amateurs) -- their characters often have a certain accent because their lips aren't moving and they are maintaining a smile
- Have mercy on amateur/community actors' mouth muscles. Think about this carefully.
I realize I am answering partly from a written context, but remember that a con-lang will be written as well, many rules are the same, and many wb.se users are into writing--so answering for them too.
Every rule probably has its exceptions, of course. You have to know your audience, subject, tone, and intent. If you intend for the audience to be confused during a short skit, and to listen only to conversational tones and impressions, then by all means, do what you need to do. Long interactions rules will be different than short ones.