There’s no need to remember the sigils. I just keep a journal with them and make permanent paper medallions, consecrated in ritual. You can save them on your phone, also. Yes there are spirits that can help teach you languages, Ronove and Forneus being two. Though I’ve used a different spirits, I’ve learned Japanese, Latin, Norse, and a couple fictional languages (enough to hold baby conversations, still fleshing out more complicated vocabulary) with the help of spirits and my own work.
There are spirits who can teach technology also. I actually passed my neurology final a few years back with the help of a manifested pop culture spirit. The thing about it though is you still have to do the work. They’re teachers, they teach you and help you understand but it still takes time to learn and practice.
If there are spirits of the same name, your intention will help draw out the “correct” one, given you know what that is. Using alternative titles helps, also.
It is possible to invoke imposters, which is usually what rituals help prevent.
Names of entities aren’t concrete on pronunciation. There’s a demon I’m personally well attached to named Cimejes, which I pronounce as “Kee-May-Ess” though he also goes by Kimaris canonically, which I pronounce as “Kim-Are-Iss.” I pronounce Ronové as if it were Spanish (Ro-No-Vay ish) and generally use Spanish or pronunciation for most entities, but you can likely pronounce them any way and still get satisfying results. Don’t get caught up trying to over prepare. You’ll just stagnate and get nothing done. Magic is very flexible.
You can also use creativity to help hone the skill you want. Cimejes is a demon said to “make men like him” which is supposed to mean “give men soldier-like qualities just like he is a soldier” but i asked him to literally turn me into a man. It’ll be a year since I asked him this, 9 months of testosterone, as well as I’ll be legally changing my name and gender very soon thanks to his help.
Spirits don’t give you, to exaggerate, the ability to snap your fingers and poof a fireball like Dungeons and Dragons, they guide you to make a fire from friction with sticks, which is work you still have to do but something you (probably) otherwise wouldn’t have known exactly how to do.