Does Geas/Quest function on unconscious targets, or when the caster can't be heard?

Question

How does Geas/Quest interact with sleeping targets, and when cast with metamagic silent-spell?

Recently I have begun to look at the Geas/Quest spell in Pathfinder, both for potential use as a GM, and as a player.

Now, the spell is language dependent, meaning the target has to be able to understand the caster, however does the command need to be issued vocally or is it transmitted mentally?

For example:

Ikbar the sorcerer has learned the Geas spell, and also has the metamagic feat silent spell. Geas/Quest only has verbal components, so by casting it with silent spell, does he then need to issue a verbal commmand, or are the terms of the geas transmitted mentally?

Furthermore, how would this spell affect a target who was sleeping? For example:

Isasneak the Bard sneaks off on his own to attempt to gather information for the party. They are in a castle, and while not regarded hostile, are still regarded with serious apprehension. He covers himself with invisibility and sneaks off. After sneaking into a room he finds the king taking a nap and casts geas on him because hey, why not. Bard shenanigans. Assuming the king isn't woken by the verbal components, will it still take hold?

Now, if you decided that it should be a mental transmission, assume the bard from case two first cast a zone of silence around him, and then cast the geas. He could still verbally speak the components of the spell, but zone of silence states that it disrupts language-dependent spells.

How does this spell interact with sleeping targets, and when cast with metamagic silent-spell?

Answer 1

Many spells and effects state that they are "language-dependent." A language-dependent spell or effect uses intelligible language as a medium for communication. If the target cannot understand or hear what the caster of a language-dependent spell says, the spell has no effect, even if the target fails its saving throw.

http://www.d20pfsrd.com/basics-ability-scores/glossary#TOC-Language-Dependent

Silent Spell doesn't give you any special telepathic powers. The casting of the spell itself is silent, but further activity, in this case direction of a subject, must be made to a subject able to hear and understand you. This can still be helpful; "Casts spell...Now let me through!" "OK." is way more suspicious to all and sundry than "Let me through!" "OK."

Someone sleeping is not able to understand you.