The latest edition of Dictionaries, the journal of the Dictionary Society of North America (disclosure: I am a long-time member), surveys efforts underway in several languages to track neologisms, which is to say, new words. You don't need much imagination to guess why people who work in the dictionary world would be interested in new words, but the research methods for finding them are much more wide-ranging and intensive than you might imagine.
Happily, new words are popping up everywhere as they always have. There are a couple of ways that a word can be deemed "new" in a language: it's a never-before seen or spoken anywhere word (rare); it's a word put together from pieces of words of various origin (common); or it's a word borrowed, with or without modification, from another language (very common).
Today, words travel from language to language with much greater facility than ever before, and lexicographers' methods for finding them grow ever more sophisticated. Both of these phenomena are a result of the same two overall trends: globalization and the intrusion of technology into every aspect of modern language research.
Does English hold a special place in the traffic of new words across languages? If your guess is "yes," your instincts are spot-on. English has long had the habit of borrowing freely from the world's languages. One reason for this is that English, fortunately, has no governing authority: no one (other than speakers, collectively) decides what's English and what's not, and those who purport to decide what's good English and what's not often get hoist on their own petard. Ultimately, English-speaking communities decide what stays and what goes. When enough English speakers decide that a foreign word needs to be naturalized into English, lexicographers just do the right thing: document the evidence and add it to the dictionary.
Just as English borrows freely from other languages, its largesse to other lexicons is unbounded. Partly because of the reach of the English-language internet, and partly because English-speaking cultures are so influential around the world, it's a rare language that can resist the push of English lexical items into their vocabularies. You can almost see it happening in real time. Want to know how to say "lockdown" in Hindi? It's लॉकडाउन, "lokdaun".
In days of yore, the search for new words was an intensive labor of love on the part of numerous lexicographers and an even greater number of volunteers in the field. The volunteers' work was to send in documentary evidence of new words and new usages to dictionary publishers. That effort continues today, for example, in the OED Reading Programme. But much more of the work today, while still labor-intensive and love-driven, is done by computers. Programs called spiders crawl relentlessly over the Internet, gobbling up huge volumes of text. Other programs, such as those provided by Sketch Engine, enable researchers to tag and parse the text (that is, analyze it grammatically and syntactically) and to generate word lists, arranged in order of their frequency in the collected text. Prime candidates for research are words that occur a relatively small number of times in a large collection of recent text and do not yet appear in dictionary headword lists.
When novelty items are located in this way, the job of the lexicographer is to determine whether the word is new, or merely rare and obscure. If the word is new, what does it mean? Does it occur in a wide enough range of contexts that a reader is likely to come across it? Is the word settled enough in meaning that it is definable? If these last two questions can be answered "yes", then the word becomes a good candidate for inclusion in a dictionary.
Three articles in the new issue of Dictionaries report on neologisms in Germanic languages: Danish, Dutch, and Frisian. Instinct might suggest that languages so closely related to English (also a Germanic language) would do their own independent neologizing, but English is a bit of a bully with hegemonic standing in the Germanic family, and even these languages often find it easier to borrow a word rather than develop their own. Thus English accounts for more than 80% of direct borrowings into Danish; Dutch has borrowed such English originals as app, crowdfunding, selfie, and pastafarian; and Frisian, even though it borrows more heavily from Dutch than from English, often takes words from Dutch that the Netherlands had already borrowed from English.
Cultures more distant from the anglophone world are a bit less reliant on English for their new-word needs. Swahili, for example (spoken widely in central and eastern Africa as a lingua franca), has historically borrowed heavily from Arabic and so today, it still finds Arabic a more friendly lender than other languages. But English comes next after it, even in borrowings for technical terms in linguistics. Greek (unlike languages mentioned up to now) has its own alphabet and so has to perform some acrobatics when adapting a foreign word for local use, but a lot of English still finds its way into Greek, even if it is not recognizable by speakers of the lending language. Examples include γουάι φάι (Wi-Fi), νάιλον (nylon), and αγκουγκλητος ("not found on Google"). English accounts for more trademark importations into Greek than all other languages combined.
Surely some of the most interesting neologisms in other languages are for things and concepts that English (so far) has found no need for. Some of these words give us a small window into cultures that are very different from ours, and Korean is a good example. It has lately developed such words as ansim-thayksi ("safe taxi", i.e., one with a female driver); koltu-misu ("gold-miss", a 30-something unmarried woman of comfortable means), and em-chin-a ("Mom's friend's son", a friend's ideal son that a mother compares her own son to).
The challenge for dictionary publishers — of whom nearly all today devote most of their efforts to their online presence — is keeping up to date. The modern online dictionary is in some ways like a boutique: if you find what you're looking for when you visit there, you're much likely to go back another time. But if dictionaries are undiscriminating in allowing new entries onto their headword list, they run the risk of appearing to be irresponsible stewards of the language, by condoning the use of words that do not endure, or whose meaning is not settled.
The perfect balance would be a dictionary that has all the words you are looking for. Of course, every dictionary would like to be that dictionary — but none can be. For that reason, it's a great benefit of the modern age that we all have access to many dictionaries online, instead of just the one that you might have received as a high school graduation present, years ago.