What are the criteria to adopt new words into English?

For a phrase to be adopted into a language, enough people have to start using it. There is no set of criteria beyond popularity.

There is no way to force a phrase into someone's language at an individual level and to make sure it means what you want it to mean.

Think of words and phrases as if they are mental viral symbionts. They inhabit your brain to help you communicate and live on your use of them. If they are of no use, they will die and they will not become part of your language.

If lots of people around you use a phrase then it will gain traction in the language of your society, like a cold that spreads around an office, and possibly further depending on how well travelled people in your society are and how useful the phrase is outside of your society.

For a phrase to be put into a dictionary, that's a different matter.

As for a neologism movement, I don't believe there is an explicit one, but OED and the like do look out for new words and phrases to include for future editions.

• First, what is a word? There's a full linguistic definition that is, even in its technical details, has some vagueness to it, especially if you consider languages other than English. Is a dog barking a word? Probably not a human one. Is 'woof' a word? Not sure. Is 'bark' (for the sound a dog makes) a word? Surely. How about 'mmm' (for 'I like the taste of that') or 'mmm hmm' for 'yes' or "'ll" or "n't" for contractions, or anything in "I-uh-no" for "I don't know". Anyway, even though it's not obvious, let's assume we all agree on noun-like things for arguments sake.

• Who decides what is a word? It seems like all school teachers have a direct line to the dictionary in the sky, but really, they're just people who are trying to do their job and keep you little brats from chewing off their own leg to escape the bear trap of secondary educ... where was I? I drifted off... oh. School teachers seem to know everything and there's only a single way to do everything, and that is very useful for communication. But in reality by the time we're five year olds and in formal instruction, we are universally, the world over, experts in our mother tongue... only by hearing other people speak. Language is what other people speak, a social product. It is not designed by a single person. It is a construct of millions of tiny arbitrary choices made by a group of people over time, with no decisions at all. So the idea of one person making up a word out of thin air, and other people adopting it is a very rare situation. It certainly happens, and as often as not the made-up word is not repeated by others.

• Dictionaries, how do they work? - Dictionaries are written by people, presumably people who have given a lot of thought to it. For any particular string of sounds, they research when and how it is used, for how long, where it came from, what different meaning(s) it has, how frequent it is, in what sub populations it might have different, etc, etc. But a person writes it. So it sounds like a dictionary is an authority and definitive. But it's not. Well, it is an authority, but in the sense that an expert who knows a lot is probably closer, more accurate than you are. And it is definitive in that it gives descriptions of the meanings of the words which are usually not wrong, but you really can't replace a word with its definition, like in math, and have it mean the same thing usually. There's more to a word than the minimal the fits in a dictionary. The OED, currently the best authoritative dictionary for English, is always being updated and edited, and they still pare things down to fit on a page. And they're on the internet which has unlimited pages.

• You may feel like a school teacher is an enforcer of laws of word-hood. But as much power as they have over our earlier lives, a word in a dictionary isn't a necessary and sufficient means of wordhood. It's a very good indication. Just not a guarantee. You are checking for all my words in a dictionary, aren't you?

• But anyway, what are the formal or informal criteria for inclusion into a dictionary? Most dictionaries have a clear confident specification of inclusion criteria written somewhere in the 5 point font in the front pages of a hard copy or on a web page that has a link buried 10 clicks in if at all. But they usually say something like "An entry (a single semantic definition) is added to the dictionary when a string is found in print (or on the web) exactly 500 distinct times (or probably something a little more vague than that)" or "we did a spider crawl of the Enternet and indexed all whitespace delimited strings and this one occurred a few times and we thought it was cool". But usually there is some deference given to the 'multiple, consistent uses'. So slang terms usually take a while to be dded, to make sure they have some traction, exactly to counteract the crazy shit that appears in Urban Dictionary (UD, you're super fun to waste a day on, but I wouldn't trust any of your definitions as far as I could through the rack of servers you are hosted on).

• Nothing I've said so far is particular to English (except for the OED) and I'll continue that way. What are the rules for word formation of new words? Spoken that way, it's common in foreign language courses to learn all the ways suffixes and prefixes can be added on to make an adjective into an adverb, or a noun into an adjective, or a verb into a noun into into an adverb swimmingly. But that's obvious and not what you're asking.

• You're asking about those Carrolian portmanteau words where two words are mushed together to form a never before seen word hat somehow means what both the constituent words mean but together but you're never really sure. Like frumious or outgrabe or clamber. (note that of those three only 'clamber' is considered a word now.)

But to actually attempt to answer your question, some vague guidelines are:

• the word has to 'sound' right. Like 'television'. It flows off the tongue. It has to work wth the syllables and accent and the phonemes.
• the word has to be repeated by others 'enough' times. 'polysemy' does not roll off the tongue at all but it labels a very useful concept and so has become recognized as a word.
• the parts have to make sense together. 'chronoceramics' will probably never become a word (you heard it here first) because, like onions and milk,the two parts just don't go together.

Wait...nothing about that was specific to English. Saying what a good new word is would be like saying what a good sentence is. There are millions of rules for forming a sentence, but is it a good sentence? I can't really list all the rules out except by those already learned in a language class. Likewise with words. But there is more opinion involved with a single word.

Wait on that wait... you're asking about neologism movement, and similar to the movement in PRC? First, there is a huge implicit movement in English-speaking society for neologism, really begun in the 15th, to make fancy new latinate words for technical situations or to obscure simple things or to compress a very complicated concept into a single impenetrable word. But this is not an explicit English 'neologism' movement.

Every so often there'll be a running column in some erudite magazine that every month proposes a handful of portmanteau words, but they're all awful puns barely worthy of worst offender Alec Trebek on Jeopardy!. Groan!

As to those five examples, it is my semi-educated opinion that they don't sound very good and will most likely never be adopted by native speakers. Some of them just don't have the right prosody (e.g. 'freedamn', where is the stress supposed to go?).

But for the most part, the problem those examples is that they just don't make sense. 'shitizen' just sounds like someone who is downtrodden or underclass, but does not sound at all like no citizen without any rights at all. That would be a contradiction in terms, because for something to be called a citizen, they'd have to have some rights. But 'shit' doesn't imply no rights. So, in my opinion, that particular word just doesn't work.

So TLDR, there's no real explicit neologism movement (but people do like to make up words all the time, and successfully so in technology) and new words have to 'sound' like English and make sense for them to catch on.

Language Log discusses these English and Chinese terms are as shown in a BBC article. Miffy has the first reference to these items on italki. The BBC and Miffy do not make it clear what the provenance of the terms is. From that list, the Chinese neologisms do seem to be new (past 15 years) internet slang in China and not uncommon, but those English neologisms are definitely not used currently in English in the US or UK.

For example,

smilence 笑而不语

the Chinese translates character by character to 'laugh and not talk', a new phrase in Chinese, and could easily be seen as motivation for the English portmanteau combining 'smile' and 'silence'.

It may be that those English neologisms are used in China by Chinese, but I can't confirm that.