A few weeks ago, on Twitter, +Wm Annis of the +Conlangery Podcast pondered whether he should add ideophones to an existing conlang or create a new one. I said "Let your conlang decide." This remark deserves a bit of explanation.
I think that a good conlang should feel like it has a mind of its own. Yes, Khangaþyagon is my creation, and I can technically do what I like with it, but whatever I do has to feel like it naturally belongs to the language. So, to start with, I don't use word generation software. I'm a committed handcrafter of vocabulary, because I have to feel I've got the right match of sound to meaning. Sometimes the word comes first, sometimes the meaning, but whichever way round it is, it has to mean what Khangaþyagon wants it to mean.
A good example is "oplen". When I first thought of it, I thought it was a verb. I'd worked out what the correct form and sense of the present participal were (Khangaþyagon verbal nouns have quirks), but I didn't have a suitable meaning (it was meant to be something to do with travel). So I slept on it, and in the morning I had the answer. "oplen" wasn't a verb at all. It's a noun, and it means "glade".
If you want to work this way (and it won't be to everybody's tastes) it's important to internalise your language's phonaesthetics. When I started work on Khangaþyagon, my wife and I were doing an evening class on History of Art. Under the influence of Wassily Kandinsky, I decided that all wizards should be synaesthetes. This set me an interesting challenge, as I'm not one myself. You should have seen me, when I was making up names for herbs and spices, going round my kitchen, sniffing at jars, trying to fit sounds to scents. I'm particularly proud of those words.
Another word I'm proud of is "dapt-" which means "be the weather". I had been thinking that Khangaþyagon would express the weather with phrases like "The sun shines", "the rain falls", "the wind blows" etc. However, during Lexember, I came up with this verb, which fits in much better with the character of Khangaþyagon. Given that Khangaþyagon is a magical language, just think of the possibilities of the first and second persons.
Khangaþyagon can reject words too. Early on, I coined egorigik and namassateus, but Khangaþyagon didn't want them. If your conlang does, it can have them.
It's not just about the words. A language's personality should pervade every aspect of its grammar. You remember I said that verbal nouns had quirks? I started Khangaþyagon by taking a runic inscription from an Anglo-Saxon ring, ærkriuflt kriariþon glæstæpontol, and parsing it as "Let the bleeding be healed by conjuration." This gave me two forms, on and ont, for what I loosely call the present participal. However, I later created words for which these forms acted more like agent nouns. Which form and which sense go with a particular verb are lexically determined, and they don't correlate. This started out as a mistake, but I liked it so I kept it.
The segunak "ut" means "at" or "exact location". "omb" means around. So why does the combination "utomb" mean "made of"? Your guess is as good as mine.
Does the verb "to be" even have a passive in any language? It's Khangaþyagon's way of expressing "there is". It seems to work.
You might say that all this talk of letting your language think for itself is all a flight of fancy. After all, aren't I the one making all these decisions in the end? But creating a language is a flight of fancy to start with, one that you have to be fully involved in to undertake successfully. This is a flight of fancy that I've been on for over 10 years. Khangaþyagon is part of me now.