Someone googled for exactly this phrase and found this blog. I will not ask ‘why, oh google, why?’ instead, I will try to look at the issue a bit. The answer of course is: it depends. And in the case you do not do a language like Toki Pona, which has a fixed set of vocabulary as part of its design, the answer will probably be ‘many’! I have more than 1700 words in rejistanian (not all are stems), but still I feel that I am not finished. Sure, I can say things like that there is no fixed order in which the home team is listed in traditional rejistanian sports, or that the train was too late and thus I was unable to come on time, but I am not sure that I could talk about everything I talk about in real life in rejistanian. I know that if I was confronted with a malfunctioning car in Rejistania, I would not be able to understand what exactly was wrong with it only based on the description of the mechanic. I know that I would not be able to ask in a rejistanian cosmetics store which foundation, eye shadow, lip stick, concealer, etc, they would recommend because none of these words exist. So from personal experience: more than 1800 words. Of course, it depends on the language. A language used by stoneage tribes needs no word for carburator or gasket. A language used by aliens with tentacles (like the Rikchik) needs no word for finger. It also depends on what a language is supposed to be used for. A naming language will not require more than about a hundred words. A language which will only be used for a specific purpose only needs the vocabulary for this purpose. However, when you want to rickroll people, ask the referee about the location of his seeing-eye dog, order food in a restaurant, discuss the latest election, tell about that new band you discovered or convince people that Bielefeld does not exist and what is really there, then you need word, lots of them.
So, while I cannot give numbers, I can tell people that the only way to deal with the creation of vocabulary is to grin and bear it. As soon as a basis is done, there will not be the need to create words all the time. If the language has a clear purpose, it will reach the point where you can see a sentence and immediately know that you coined all its words far quicker, mostly because you have a clear direction into which to direct your effort without being distracted by attempting to explain to people that Bielefeld does not exist and what really is there in your constructed language. It also helps to have lots of ‘Unabsteigbarkeit’ in your language, ie the ability to create a word from affixes (intolerability is a good English example), as well as much compounding but not a cure-all. Some compounds make little sense unless you remember the reason behind them, so they have to be documented just as well.
I guess my significant other has a much more laconic way to answer the question though:
(Rejistania) In the category ‘who googles such slani and finds the RWotD’, the prize goes to that person who googled ‘how many words does a conlang need?’
(Allanea) the answer is simple
(Allanea) M
(Allanea) O
(Allanea) A
(Allanea) R
He is perfectly right. I can imagine that even after a century of using and improving rejistanian, the future me will find new lexical gaps. And IMHO that is a great thing.
eljanicator provided some numerical values, which probably work well as ballpark numbers:
I don’t remember where I read it exactly, but I’ve heard that a very limited special-purpose language needs at least 100 words, a trade/diplomacy pidgin needs at least 500, a fully functional language for everyday communication in a wide variety of subjects needs at least 2000, and most modern-day real-world languages have at least 6000. Many have considerably more. The very “largest” ones have a few hundred thousand, though in that case most people who speak it only actually know a small fraction of the total, as the bulk of the language consists of highly specialized or exotic words that most people don’t really need or encounter in ordinary life.
The word of the day for today is ytanu’het which means neck or rather the same as the German word ‘Hals’, ie: everything between the level of head and shoulders.
Example: Ytanu’het’xe mi’tore. (neck-GEN1S 3S-hurt: I have a sore throat)
Rejistanian Word of the Day 
Good post. Even a natural language is always expanding, with words being coined, reapplied, borrowed or rediscovered for all manner of reasons. The answer “more” (or “moar”) is definitely right. In my first dedicated conlang I reached about 630 words – whenever I wanted to write something I would need to create more! I don’t know how many my current main conlang has, because I have been very disorganised with making a lexicon for it, but it has a loooong way to go before it would be useable in everyday life (supposing such a situation would arise anyway).
Is your conlang somewhere on the web? I always like to see the work of others!
For everyday usage, I sometimes try to translate some interactions into rejistanian. Like how to buy a newspaper, or how to ask whether the train was already there and when the next one will arrive. Such things IMHO make the language immediately more usable and they can be done in daily life.
Just make sure you are awake enough not to, frex, talk to the guy working at McD in your conlang…
I have a few bits and pieces of various conlangs here and there, but I’m currently working on a proper lexicon and grammar (well, at least a part grammar) to hopefully put us as a website. Seeing the constructions of others is always fun and inspiring to me, hence how I found your blog!
Such translations are a good idea, thanks. I sometimes find myself wanting to express certain sayins in my conlang, or to use a certain conlang word rather than the English one. (Because I take the approach of coining new words as I go, and for personal satisfaction, instead of using a word generator/protolanguage etc.)
Awesome post! I am embarrassed to say that in my younger days of conlanging I googled similar things. I don’t think I ever found a real answer layed out like this, just various bits and pieces to reach the same conclusion 🙂
I have no idea just how many words published conlang, Reisum has. I could count the items in the wikitionary, but that’s only ones I’ve published online of course. Just thinking of the time it would take to count them right now… It would be better to spend my time getting them all online, and just counting them easily then.
Counting? You just need the right pattern for grep 😉
I don’t remember where I read it exactly, but I’ve heard that a very limited special-purpose language needs at least 100 words, a trade/diplomacy pidgin needs at least 500, a fully functional language for everyday communication in a wide variety of subjects needs at least 2000, and most modern-day real-world languages have at least 6000. Many have considerably more. The very “largest” ones have a few hundred thousand, though in that case most people who speak it only actually know a small fraction of the total, as the bulk of the language consists of highly specialized or exotic words that most people don’t really need or encounter in ordinary life.
Do you mind if I cite your comment in this posting. This seem to be good ballpark numbers.
Sure, go ahead. As much or as little of that as you think is relevant.
I often find it helpful to begin with a fairly primitive stoneage-type language (like protoindoeuropean) or make one up, then apply sound changes to a few different descendents. The changes continue to a modern phase, with interborrowings or compound coinages along the way. If a new topic is introduced (say, a new fruit from a tropical region), then the word used by the native growers of the fruit would be borrowed. This can also work for migrations. In an atlang that I developed (with help from my sister), a long series of events leads large numbers of indoeuropeans through a century of assimilation in China and a subsequent migration to Japan, where older, PIE roots are replaced by Japanese loans, eg xilba: “forest (pronounced shilba) from PIE kselwaa is replaced by loanword semydor from Japanese semidori. This can also allow for different class and age distinctions where older forms are used by the upper class or elders and loanwords are used colloquially. (by the way the altlang begins with Cleopatra NOT committing suicide). I have used this internal and external borrowing many times and takes the load off of coining new words; instead, borrowing or forming compounds from a smaller and older lexicon.
Quite impressive, but for me it would appear pretty impossible to start from such an early level and remain at the depth I like with my conlangs. Is your work someplace?