There's a limit in range. If you want to yell at Kratos, it will require a voice or his physical presence.

[Yuan is guessing that Zelos is more angry with Kratos than with Yuan himself; though standing in the way won't help Yuan's case. Well, he can take Zelos's ill opinion of him anyway -- not that there would have been a good one in the first place, not that Yuan cares except as it affects the Tree -- and the emotion will help Zelos make himself understood better.]

[He keeps drifting, winging this way and that. Lightning, without warning.]

Sufficient emotional projection will produce something of that effect, yes.

Try it with me and the next thing I cast will be Spark Wave.

[Yuan has no fondness for screaming inside his head.]