Benefit: You can maintain concentration on one spell of the illusion school as a swift action. This has no effect on spells of other schools or on illusion spells with durations that don’t depend on your active concentration. While you may only maintain one spell as a swift action, you may take your move and standard actions to maintain other spells normally, if you wish.
Spellsong
You can blend the power of your performance and spellcasting.
Prerequisites: Cha 13, bardic performance class ability, able to cast 1st-level spells.
Benefit: You can combine your bardic performance and your spellcasting in two ways. First, you can conceal the activity of casting a bard spell by masking it in a performance. As a swift action, you may combine your casting time of a spell with a Perform check. Observers must make a Perception or Sense Motive check opposed by your Perform check to realize you are also casting a spell. This uses 1 round of your bardic performance ability, regardless of the spell's casting time.
Second, as a move action, you can use 1 round of bardic performance to maintain a bard spell with a duration of concentration. You can cast another spell in the same round you are using bardic magic to maintain concentration; if you do this, your concentration on the maintained spell ends when you end the bardic performance the spell is part of.
Could you use the first part of spellsong to attempt to hide the casting of the illusion and then use effortless trickery to continue the illusion? (In other words; can you chose not to do the second part of the spell song and continue the spell normally or with effortless trickery?)
Example:
Round 1) Use Spellsong to cast silent image using up one round of bardic performance.
Round 2) Maintain concentration on the spell using effortless trickery as a swift action and then use your standard action to use Weird Words or cast a spell.
If you have illusion between you and the enemy could a Sound striker bard use his supernatural weird words through said illusion without giving away the illusion or his position? How would not being able to see his/her opponent effect my enemies ability to defend itself (would it give +2 to attack rolls and ignore dex to AC like invisibility)?
If you used vanish and then weird words would all of the attacks ignore dex and have +2 or just the first one?
Looks like it should work, yes. I'd be a bit odd to Perform something the one round, and then just seem to stand there the next though.