Oh that would be a very fun project! Make every sound just a different kind of vowel, skip all the consonants entirely. Make sure each word has vowels that are very similar. Every word should be very long as well.

Everything should have conjugations, and you should be able to stack them infinitely. There should be lots of prefixes and suffixes you can sprinkle liberally everywhere.

The grammar should have zero consistency. Everything is just a never ending list of exceptions. You would need to have a degree in cryotherapy to learn this language.

The classification of words and linguistic structures should be so bizarre, that existing systems wouldn’t be able to handle it. None of this fits in any box we already have. It should be so unique, that no other language would help with it.