[Keroko]

Originally Posted by Tormenk

There was a scene in the manga where Vivio was innocently perusing videos of both Nanoha and Fate in action. I'm more inclined towards the "she can learn by observation" rather than simply..being in the proximity of a person.

Correction, she was viewing a few of Nanoha's training manuals. While that excuses Nanoha's moves, she has never seen Fate in action, so the only way she could have copied moves from Fate would be that it copies from her directly. Perhaps a-la Yami no Sho.

Originally Posted by Jimmy C

Copying skills is one thing. What really matters is can she actually use them without additional support like the Relic or the Cradle? Because if she can't, it doesn't matter.

Doubtful. Otherwise she would have gotten Kris a long time ago.

Originally Posted by PhoenixFlare

Ah, yes, I've forgotten about that. That in itself may be a rarity introduced by her genome. Yet, like Jimmy pointed out, can she also use those copied skills without some of the prerequisites? For instance, can she use lightning-based attack without the mana affinity conversion ability present in Fate or Erio?

Considering she 'converted' Fate's copied abilities into purely magical ones rather than using lightning, I'd say no.

Originally Posted by PhoenixFlare

That said, "skills" in itself is subjective. Is reading a skill, and if it is, did she copy this? Talking, too, can be considered a skill, and did Vivio learn how to talk, or did she copy it?

Magical skills, of course. This was highlighted in the anime as well, with Vivio saying it was the gathering of magical data. Talking was attributed to her having memories of her past life as part of Project F. So it was technically something learned the usual way, albeit in a past life.