What if I get stuck?

This may seem odd, getting stuck when making a constructed language, but occasionally I get confounded with words. I play with Latin and Old English, but I don't know the languages. There are rules to building Illunse words, such as that I'm limited in the letters that I can use. Sometimes I can't seem to mix the Latin and the Old English words in any allowable way that I like. When that happens, I usually try another word, and come back to the skipped word later.

I prefer for my Illunse words to vaguely resemble the modern English word or synonym of it. Of course, that is not always possible. Some Illunse words look somewhat like the Latin words, especially when the Latin word -- or a derived Spanish or French word -- is familiar to me.

Lately I seem to be working with ancient terms, such as walled towns and castles. Someday I'll want to define a word, but won't find it in archaic languages of Old English and Latin. Then I'll be truly stuck. Perhaps, I could try using Middle English for Old English. I actually do have a Middle English dictionary. But for Latin, what do I use, Italian? When I get stuck, I'll figure something out.