Here is a Guide detailing the differences in effect between the various Chant and Echo skills.
Anthem: An Anthem is a Chant that affects allies within earshot. Whatever effect is specified by the chant occurs when an affected ally uses an attack skill. The chant then ends on that ally.
Aria: An Aria is a Chant that affects allies within earshot. Whatever effect is specified by the chant occurs when an affected ally casts a spell. The chant then ends on that ally.
Ballad: A Ballad is a Chant that affects allies within earshot. Whatever effect is specified by the chant occurs when an affected ally takes damage. The chant then ends on that ally.
Chorus: A Chorus is a Chant that affects allies within earshot. Whatever effect is specified by the chant occurs when an affected ally uses a Shout or a Chant. The chant then ends on that ally.
Lyric: A Lyric is a Chant that affects allies within earshot. Whatever effect is specified by the chant occurs when an affected ally uses a Signet. The chant then ends on that ally.
Song: A Song is a Chant type that doesn't have a consistent enough effect to classify them. Read the description for each individual Song for their effects.
Finale: A Finale is an Echo, which only affects the singer or a single ally depending on the skill. If the target has a Chant or a Shout ending on them, then the Finale effect will occur. Finales do not end after the effect has occurred.
Finales are also an Echo like Refrains, but are much more tricky in their application and how to gain the most benefit from them.
Unlike Refrains, Finales are not automatically reapplied, but with careful management, you can potentially reap a much bigger effect from a Finale.
Finales are special in the way that during their duration, they give their effect to the ally carrying the Finale, when a shout or chant expires on said ally.
It is here that having a spammable shout or chant with a short duration really shines. You can really milk the Finale for its power by using this technique. And is why Warrior appears to be a popular choice for a Paragon secondary. The Shout “Watch Yourself”, with 0 ranks in Tactics, lasts 5 seconds, meaning that a Finale with a Duration of 30 seconds will give it's effect roughly 6 times.
At 12 ranks in Motivation, Finale of Restoration lasts 30 seconds and gives 63 health to the ally each time a shout expires on them, allowing you to present a constant stream of healing.
Refrain: A Refrain is an Echo, which only affects the singer or a single ally depending on the skill. If the target has a Chant or a Shout ending on them, then the Refrain is reapplied, recasting it for free and resetting the duration on it.
A Paragon casts Mending Refrain on a Warrior who is the tank of the party. Mending Refrain is an echo, costs 10 energy and lasts for 20 seconds. Providing up to +3pips of regen.
Normally it would just run out after 20 seconds, meaning you would have to manually recast on it on the target. But! Since it is a Refrain, you merely have to cast ANY Chant or a Shout WITHIN earshot range of the target and have that Chant or Shout end before the Refrain runs out. Your ally will need to stay within earshot range but when the shout or chant ENDS the refrain that was cast on him will be recast for free, resetting it's duration and making it last longer, WITHOUT the Paragon needing to worry about it.
This means that you can essentially get Mending Refrain up on your entire Party and maintain it indefinitely, as long you keep reapplying them with an expired party wide Shout or any expired Chant. It is here that “Watch Yourself” shines, since it is spammable and only takes 4 adrenaline, making it a perfect tool to keep the Refrains running. Additionally, with high enough Leadership, you can cast 5 energy chants, or party wide shouts for free, and use it to keep the refrains going forever when out of adrenaline.
If you don’t want to use “Watch Yourself”, you could combine Mending Refrain with the EXCELLENT elite chant Song of Purification, which needs just 5 adrenaline and has no recharge. Providing virtual immunity to conditions (The effect of Song of Purification) as well as keeping up the Mending Refrains each time you use Song of Purification.
A support Paragon will be able to take a LOT of pressure from the monks once he gets started on singing.
Alternatively, if you want to be more offensive instead of offering defensive support, there are other choices.
You could combine the popular chant, Anthem of Flame with the Echo skill, Burning Refrain to really crank up the Burning your party can put out. Once all party members have Burning Refrain on them it can be relatively easy to maintain this as you will keep refreshing the Refrains with Anthem of Flame as it expires.
Each time your friends attack with a skill, causing burning, they end the Anthem of Flame Chant and reapplies Burning Refrain.
Anthem of Flame costs energy, meaning you don’t need to build up Adrenaline beforehand to keep casting it like Watch Yourself, and it will effectively be free at 10 Leadership.
Combine this with 'They're on Fire!" to reduce the damage your friends take from burning foes. Add in the superb Blazing Spear for even more fiery goodness.
I thought it might be somewhat confusing for budding Paragons with all these odd sounding skills with such similar, yet subtly different effects. Prompting me to write this guide to the Vocal Arts of the Paragon, which I hope will prove useful.