It's only slightly creepy that you know a language "fluently" without knowing the name....

I have long concluded he/she is a linguist making fun of us.

This is interesting. Is this supposed to be a conlang, or what? You said you didn't know where it came from or something, so you must have made it up. How would there be any possibility of its being a real language? Does it have a name?

I'd only believe him or her that he or she learned it if he or she can prove us he or she has cryptomnesia or something like that.

I find it possible for one not to know the name of their language, but this is strange overly strange… With nothing better to do, I present my first linguistic proof.

I did a quick run through to classify the language assuming it is not a conlang. The only languages that have the vocative are Indo-European, even though there are some hints outside there. The language does not inflect enough to be Slavic or Romance (from what I know). And it is definitely not Germanic, as anyone can tell. That leaves the Balkan and Caucasian Languages. Albanian's syllable structure is different, Greek's phonology and structure are not similar, and the phonological inventory is too small to be Caucasian. It's pretty obvious it's a conlang because it looks like ninety percent of the conlangs I have seen so there. At least that's judging by the first example. Knowing that the first is a conlang, I can assume that the second is also a conlang without going into the heart of Swaziland to figure out the clicks.

As a conlang, not bad. Depends on your purpose.

What's cryptomnesia?

It must be a Conlang after all, although I'm positive there are some influences from existing languages. I'm too uncreative to create everything all by my own, I'd suppose.And I've always used existing languages when creating a new one:)
As to my promised grammar, I thought about the neccessity of an evaluation. And considering it has approx. 20 cases and 8 tenses to express everything as it should, I thought it might not be that demanding to have one. Also, there are about 10-20 sounds not expressable with IPA or any script I am aware of(a sample, the language's name written "Cusanahusa" in latin script, is spoken with the "c"-sound being roughly the sound breathing in while saying "j", the two "s"-types are both similar to the sound of wind, however, with almost unrecognizable changed position of the tongue, which is rather important to identify some words. The "h" is roughly the sound when you speak "ɺ","χ" and "ɾ" together).
On the other hand side, I guess a grammar would be useful for a conlang. What do you think?

Cryptomnesia(taken from Wikipedia): Cryptomnesia occurs when a forgotten memory returns without its being recognized as such by the subject, who believes it is something new and original. It is a memory bias whereby a person may falsely recall generating a thought, an idea, a song, or a joke, not deliberately engaging in plagiarism but rather experiencing a memory as if it were a new inspiration.

I think I get cryptomnesia a lot. Just not that bad…