Here's the
music video. You can see which parts Yuna sings. Her vocal talent is better than I thought. It's too bad I can't understand Korean.
Even if I understand the lyrics, well, perfectly, the problem is my English.

If you endure my poor translation, this is for you.
IU : Wherever your feet touched, they(ice flowers, your sweat and tears) blossom one by one and it is getting bright without notice,
Yuna : all the things to overcome and your worries about losing are already far behind,
Yuna : I dream those dreams
IU : where there is beautiful me without having to shine.
IU : Dream, I am not sad even if I cry, just my aching heart is melting away.
Yuna : Look at me with your heart, not with your eyes, another me who will blossom inside once again.
IU : When I stand alone where there is no eyes, no applause,
Yuna : When I can smile where there is only me who sees me,
Yuna : I believe myself who can do it,
IU : myself who can love me.
IU : Dream, I am not sad even if I cry, just my aching heart is melting away.
Yuna : Look at me with your heart, not with your eyes, another me who will blossom inside once again.
(guitar)
IU : Looking back to see how far I have come, there are so many footprints
Yuna : That is it, I am doing well, for it is my life, my way.
IU : Dream, I am not sad even if I cry, just my aching heart is melting away.
Yuna : Look at me with your heart, not with your eyes, another me who will blossom inside once again.
IU : Dream, if I hold out my hand, do not be surprised. Without saying a word, would you put me back on my feet?
Yuna : Walk with me for a while, along the road widened as much as one person can widen.
I love the Korean lyrics... for anyone who understands Korean.
IU : 발길이 닿는 곳 하나하나 피어나 어느새 환해진 그 곳에
Yuna : 넘어설 무엇도 뒤처지는 걱정도 어느새 멀어진 그 곳에
Yuna : 난 그런 꿈을 꾸어요
IU : 빛날 필요 없이 아름다운 나를
IU : Dream, 나 울어도 슬픈 게 아니죠 아픈 마음이 다 녹아내릴 뿐
Yuna : 나를 눈이 아닌 맘으로 봐요 그 안에서 또 피어날 나를
IU : 눈길이 없는 곳 박수갈채 없는 곳 그 곳에 홀로 서 있을 때
Yuna : 나만이 오롯이 나를 바라보는 곳 거기서 웃을 수 있을 때
Yuna : 난 그런 나를 믿어요
IU : 날 사랑해 줄 수 있는 내 모습을
IU : Dream, 나 울어도 슬픈 게 아니죠 아픈 마음이 다 녹아내릴 뿐
Yuna : 나를 눈이 아닌 맘으로 봐요 그 안에서 또 피어날 나를
IU : 어디까지 온 건지 뒤 돌아보면 저 많은 발자국들
Yuna : 그걸로 됐어 난 잘 하고 있어 내 삶이니까 내 길이니까
IU : Dream, 나 울어도 슬픈 게 아니죠 아픈 마음이 다 녹아내릴 뿐
Yuna : 나를 눈이 아닌 맘으로 봐요 그 안에서 또 피어날 나를
IU : Dream, 나 손을 내밀면 놀라지 말고 날 말없이 일으켜줄래요
Yuna : 나와 잠시 함께 길을 걸어요 한 사람만큼 넓어진 길을..
Ice flower means sweat and tears shed on ice and the whole lyrics were inspired by Yuna's Vancouver performances.