Don't mean to cause alarm, but have you considered seeing a Doctor about this, I would rule out health problems before suspecting its past life pure blood witch nonsense.
heart of gold n mind of silver. your chat had send chills and shivers. in the past lies the dragon. the tonge thats cast from heaven. he ma ha thay su thor hel monthra arbok so mor. see if you understand these word. the sing for the sisters third. the gardians of the night. riseing aging for eternal fight. the songs that goes in your heart is the protection from the start. use it wise to do your part, but remember this young one. or heed my waring you'll be torn. with heart of good the light youll see. in heart of evil darkness youll be.
Sigh... it works because you never doubted and you focused on the intent (and hopefully you projected energies and programmed them to make the desired effects, otherwise I will not believe they really worked, for everything needs fuel or energy to run, even magick and psionics), so... yeah, you did that till it worked, a language that you don't understand is kinda helpful if you want to avoid doubting yourself.
For example I casted as spell to protect me from a mouse trap:
Let these light *blah blah blah* protect me from a mouse trap etc etc.
A language that you can understand... can raise the chances of the feelings of doubt to appear.
But if you chant these kind of spell:
oghdogheobneosgnrtwgwfwdlhknelkr;jhr;
Yeah, as gibberish as that, BUT you KNOW that if you finally chanted it and placed your energy on it, you programmed this energy with your intent, then it will work, or at least the sense of "doubt" will be banished, then it will work, you are protected from a mousetrap.
In the end, chants are just used for showmanship or to help the mage to focus on the energy manipulations he/she is going to perform, in other words, chants or incantations are just accessories that are not really needed especially if you finally learned to rely on Energy Programming and sending it out to do it's work method, ALONE.
Well that's how things works, no big deal there.
Regarding the chants appearing though, it maybe from a spirit guide, try asking Rev.Bob Hickman at YouTube, just search for "spiritchannel" that's the name of his channel, and he can answer your question, PM your question to him, otherwise, I guess you may have some kind of brain problem, try consulting a psychiatrist if the former method (asking Bob Hickman) failed.
Maybe it is your subconscious processing brain chatter into gibberish. Thats what i always took it as lol. I sometimes hear different chants, they sound native american-ish.