I don't think Galad can learn but I will say this; at the end of tGH Rand seized saidin when he was fighting Ishamael but didn't use it.  Possible but unlikely Galad can channel.

One thing also to take note...

Narration and beleif on 'channeling' is based on 3000 years of assumed belief and teaching.

We have discovered that severing can be healed when they said it was impossible, a new way of healing that doesnt weaken a person as the old style did, references by the forsaken that these Aes Sedai know less than 10% of what they knew back before the breaking etc...

There is ALWAYS the necessity to hold in the back of your mind that what is known, isnt necessarily what is.  The world is changing... almost like a Wot 2012 scenario, and when this is occurring, all bets are off.

Anyway even if Galad isn't a sparker (which i think he is) and he is a learner isn't it possible he has learnt to embrace the source through the flame and void training without ever actually channeling? Therefore he could be taught at anytime should someone try to teach him. I can't wait to see it happen because before reading about the Galad Vs Valda battle i thought Galad was a pretty pointless and annoying character. It's opened up so many doors for where his character can go. He always does what is right no matter the consequences so if he finds out he can channel will he hand himself over to the Red Ajah or something?? Or will it destroy him from the inside out? Oh the inner turmoil lol

Well...

Imagine if your Mother ran away, and your father was killed at some points in your life.

It seems that Galad had to both grow up sooner than normal adolecents do (Like LAN), and was in a palace where he turned from First in Line to red-headed step child.

Both Lan and Galad have a seriousness that shows a shell created to protect themselves from early life trauma.  His bitterness towards Rand wasnt personal, just a protective reaction... part of the persona he took on in his fractured life.

Im waiting for Galad to LEARN that Rand is his Half-brother and Kin to his mother instead of father like Gawyn and Elayne are... plus, he may find a kinship with Rand if he was told that his mother was compelled to do this by the pattern and NOT for abandonment of her son.

But... since ALL Camelyn queens were required to be tutored at the White tower, and Rand was born with the Spark from his Mother, it seems feasible that Galad could be inclined as well.

If you notice Morgase was of little power and passed the spark to Elayne, but not Gawyn... but Tegraine passed it to a male (Rand).

Could be grasping at straws here, but who truly knew the mind of RJ.

You all forget...

When mazrim Taim went from town to town looking for MEN to form the black tower, he pulled MANY of them of all ages.

The test was to see if a spark could be pulled from them... NOT to simply question if they had channeled before.