Imaginem does not affect the Senses (those are in the Me and Co GL)
Imaginem affects "Sensations" - the abstracted things which pass from pobject to perceiver, known in ME as "Species". Images, Scent (as opposed to the vapour which emits Scent species), Sounds, Texture, are all emitted by objects and picked up by those with senses.
Minds have ideas, and the understanding of words in ME is about Ideas. Hence translation is Mentem, and Books cannot be translated, nor codes deciphered, by Hermetic Magic. (The best you can do is read the mind of one who can read a text!)
"Telepathy" per se is not a Medieval idea, but starts sometime around C19 with the interest in Mediums and Mentalists.
ArM does not simulate well the C19 period, indeed turns its back on ideas prevalent then and later, and introduces various wacky ideas from ME, like Species).
Best to drop the word "Telepath" and try to rephrase the ideas in a way more in keeping with the time period, and get the players into the role...
As for the InMe 15 GL - it means "the one person designated as the target of the spell"
I would interpret it as "transcending the language barrier", just like InTe or InAq directly inform you of the answers to questions.
You could have a Sense Target, such as Hearing, to give the caster or a single person an Inme understanding of speech. Since Sense spells constantly shift what they sense, I guess that would be more like Tongues - understand the words of the person you are focussing on.
(But that would not grant the ones you Sens with the power to understand you, even if you understand them! That's back to CrMe)
You can grant a sense to one other with InXx, but for a group to get senses, you need MuMe(InXx)