How can you create, copy or transfer skills into someone's brain? So you can give your travelling companion Latin 5 when in Rome, or quick-learn how to use that sword in an emergency with Sword 3? Feels like a Creo Mentem spell, but I cant see any guidelines?
Given the mediavael paradigm includes such concepts as Memory Palaces I could see a magi transferring or copying the structure and content of their memory palace to another.
SJE
There are no Guidelines (afaik).
You cannot transfer skills or copy them , even temporarily.
If you consider skills an Improvement , use Creo , but at the same level as improving characteristics.
I would use Rego (Muto) (Co , Me) with anyone that has the skills you need.
Rego to copy the skills and Muto to change the person you "give" them to ,
as they are not skills "natural" to that person.
As Ravenscroft says, there are no guidelines for this and the discussion of mind in several of the books seems to discourage this, for obvious out-of-character game reasons. It's an area to tread lightly on because of the potential for overpowering learning rules.
The only precedent that I'm aware of is the Thoughts Within Babble spell which uses InMe to borrow someone's language speaking ability. At least, that's my interpretation of what it does; nothing is explicit. I had a version at one time that added complexity magnitudes to also share reading ability. I could see this expanding into sharing Lores and similar skills but I would probably rule that social and physical skills are too unique to an individual to be shared this way.
Memory palaces can be a lot of fun. The Memory skill in Mysteries 5th edition is particularly weak but there are some spells in the 4th edition Mysteries that you could adapt to provide magical enhancement. For game reasons though I would make magical memory palaces only a store of memories rather than the sort of processed information that provices skill points. You could memorize a text but it wouldn't give you Lore, rather it would allow you to quote the book or to refer to it through meditation.
Well, it seems to me that skills are too complex to fit in a memory palace but anyway.
Assuming you can find a way to get a master es art of memory transfering the content of his palace :
In a 'basic' locus, a realy good Art of Memory practicer can memorise up to 1 full day debate (and it's on a 18! ease factor)
For low level skills (1 maybee 2) it's may still be quite not too highly technical subject, but higher skills level or tricky ones car have a +3/6/more modifier on the ease factor.
So mainly it will be about memorizing a teaching course... which is usualy about 80days for a season, so 80 basic Locus per season of teaching.
I think we can also assume that having a vivid memory of the teaching course is way more efficient than just having the average memories resulting of a "basic lesson". So i'd probably double the 'virtual skill source'.
So, let say : vivid memory of a one season-long teaching course done by a realy good teacher (com 3, good teacher, teaching+mod 7, +3, +6one to one) 24, time 2 : 48 ! So quite close to a lvl 4 skill.
But 80 locus mean... 16 in art of memory... it doesn't seems to be reachable... let say 5 in art of memory dedicated to this for approx 1/3rd of the memorised training course and you're on 15xp, enough for a lvl 2 skill. At the expense of 20! locus that have to be untouched as long as you want to be able to implant it.
Then with 20 cast of a variant of Enhance the Memory Palace, you can implant it in somebody's mind for 1 moon. (but i'd suggest strong warping for 20 moon duration strong spells on the poor lab rat :p)
You can probably do way more using the 'Super Locus' created by the rituals linked to art of memory, but gods... such a huge amount of Vis for this.
So.. i'd say it's possible ! Somebody working hard as hell during maybee ages, to memorise a whole teaching course, can probably implant it in warped-to-be grogs for one moon. And have to keep it in memory as long has he want to enjoy the use of this 'power'.
Or you can pay a teacher who, in one season, will teach a handfull of your grogs how to speak latin 
But you can probably do it ! 
That's realy closer to the Diskworld (Pratchett) magic than the usual ArsMagica one, but that sound so fancy ! I have to speak about this with my SG
For any skill with a physical component , such as swords , i would use Corpus also.
Everyone learns skills differently , all Scribes , while able to write clearly , do not write in exactly the same way.
If you (can) copy skills , they will not adjust themselves to fit a new mind or body.
Which is why i suggest Muto to alter the skills , as possibly easier than altering stats (of the recipient) to fit the skill.
Should you allow transfer of skills , then they will be used in exactly the same manner as the originator of the skill.
Someone speaking borrowed Latin will speak identically (same accent , timbre of voice , etc) to the original.
This could sound rather odd , given physical differences and could be mistaken for Possession , as a story hook.
You simply can't with a Breakthrough. The Jerbiton rules talk about how close magi have come to this.
Another way of doing it is to borrow a faerie pretence.