I'm kind of a language nerd sooo yep, I have definitely dabbled in fictional tongues. Twice, in fact!
The first one was created when I was young and has very awkward grammar rules, mostly based on English because yeah. The second one was created some years later, and has more unique grammar, but less of an extensive dictionary than the first since I've spent less time on it. I can write complete sentences in both though—sometimes when I'm feeling extra nerdy, I'll try and rewrite an entire song/story in the fictional language. It's pretty effective for knowing what words might be needed, lol.
They also both have their own alphabets. Here's "hello" in both languages because I'm a nerd

idk if either of them would be effective as actual languages but whatever, it's fun