Creating a language for your fantasy (or not fantasy, if you like) world is, in my opinion, one of the most fun and important parts of storyworld creation. There are several ways to create those words, you can throw letters together, use a generator, go for a specific sound, or alter an existing world.
Throwing Letters Together:
This isn't my favorite way to create a word. My detail orientation kick in and I spend far too long moving letters around until I'm satisfied, but then I'm likely not going to be satisfied next time I log onto my computer.
However, this is a method that works for many people, so you need letter dice, cut up paper with a letter written on each (one for each letter of the alphabet), or a online letter generator like
Random.org
I will be using the last one, but the principle is the same, you want a completely random string of letters. On random.org I chose to have ten 'strings' (think words), ten letters long, with lowercase letters and each string should be unique. My results were:
blijaucwsd
ydtqntvszj
xxtjxstkbm
tpatazoqpl
viccrxtvml
wdoozdayfv
agwsmgnsbu
iyihqahygz
vmiwagiosm
zssilqobob
Well, those look weird. Okay, I'll use the first one blijaucwsd as my example. So I like the sound of the beginning blijau, but because (to me) the 'i' looks strange beside the 'j' and the 'l' I'm going to drop the 'l' and my result is 'bijau'
Use a Generator:
In this method, we are using a similar method to above, getting a random string of letters that could be a word, but we're using a fantasy word specific generator.
Both will generate long lists of words, using Rink Works I got this list:
Fidan | Radrodo | Ight'ton | Ridelough | Undlor | Byshy | Rayaw |
Vorgarenth | Honys | Ildt | Usk'ler |
So once again I'm going to take the first word, Fidan, and and change it around a little. Fidan, to me, sounds best with a long 'a' so I could write it as Fidān, and I want a long 'I' as well, so I might even write Feedān, or Fedān.
Go for a Specific Sound:
(Uh, not recommenced, but I've done it, whoops)
For example, in my poem about a character named Luminia, I was bored and writing it in math class long before I intended to compile my stories into a book, and I wrote about trees. For the next line I needed a rhyming word, and I wanted to talk about Luminia's family, so I named her mother Manrees.
Alter an Existing Word:
I have an academic background in Latin, I've taken three years of it in High School (because I failed the first year, languages are hard, so pay attention in class). So some of my early words in my stories are Latin words written backward with letters added or subtracted.
For example, Carpe, meaning, seize. We'll write it backwards, which would be eprac. Now I can make my changes. Maybe I want to add letters - eaprac - subtracting letters gives me, erac. Or I could add and subtract letters and get eracas.
In Conclusion:
The most important thing is that each language sounds like itself and different from others. Latin sounds very different from Chinese, but Italian (which developed from Latin) sounds similar. (English is just plain a mess).
And remember, you've created these words for a reason. There's no point in creating the, if you don't plan to give them a definition. Even if you don't use the language as dialogue between two characters, you can use it to create names that have meaning to that character's location or personality.