I have a question about Song of Freyalise. Chapters I and II say:
Until your next turn, creatures you control gain '{T}: Add one mana of any color.'
According to the wording of this effect, my creatures will gain the {T} ability until end of turn or not? How does it work?
According to the wording of this effect, my creatures will gain the {T} ability until end of turn or no?
Not exactly. The card says 'Until your next turn', so that means you can use their mana ability during your opponent's next turn (or turns, if it's a multiplayer game or they cast Time Walk) as well. Only when it's your turn again will the effect stop.
Adding onto Glorfindel's answer, here's the exact timeline of what Song of Freyalise will do for you (assuming you don't do anything weird like adding or removing counters).
When you first cast Song of Freyalise
I, II — Until your next turn, creatures you control gain "Tap: Add one mana of any color."
Song of Freyalise enters the battlefield with a Lore Counter on it (One counter Total). At this point, all creatures you control gain the mana ability on the card. They will keep this ability until the start of your next turn.
First Opponent's turn after casting Song
All your creatures still have the mana ability. You can use the ability to pay for mana costs during your opponent's turn. You keep the ability for each of your opponent's turns (as Glorfindel says, that includes extra turns and turns for each opponent if you're playing a multiplayer game).
Once your next turn starts
All your creatures lose the mana ability. This means that you cannot use the ability to pay for costs during your Untap, Upkeep, and Draw phases.
Once your Draw step ends
I, II — Until your next turn, creatures you control gain "Tap: Add one mana of any color."
You put a Lore Counter on Song of Freyalise (Two Counters Total). All your creatures gain the mana ability back.
Opponent's turn after you put a second counter on Song of Freyalise
This is the same as the last cycle of opponent's turns. All your creatures still have the ability, and they keep that ability until your next turn starts.
Once your next turn starts
This plays out exactly the same as the last time. Your creatures lose the ability and cannot activate it to pay costs during your Untap, Upkeep, and Draw phases.
Once your draw step ends
III — Put a +1/+1 counter on each creature you control. Those creatures gain vigilance, trample, and indestructible until end of turn.
You put a Lore Counter on Song of Freyallise (Three Counters Total). Your creatures do not regain the mana ability. Instead you put a +1/+1 on each creature and give them Vigilance, Trample, and Indestructible. You also now sacrifice Song of Freyalise at this point as you put a 3rd Lore Counter on it.
At the end of your turn
Your creatures lose Vigilance, Trample, and Indestructible, but keep the +1/+1 counter.
