May I ask you to show us your effort? I mean, did you try to write down the lyrics by yourself?
Sure.. here's what I've got so far.
I wrote this in hiragana (now I can cause I changed computer) and romaji since I don't know the meaning:
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1. The ( [letter] / [letter] ) is the one I'm doubt the pronunciation between these two letters in the song.
2. The ( [letter] ?) is the one I'm doubtful if it is supposed to be pronounced or not (he pronounced it not clear enough in the song).
3. The ( [letter] / [letter] (?)) is the combination of the two cases above.
4. The way he say "が" sometimes came out as "んが", as referenced in the lyrics
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HIRAGANA:
もしぼくが(pronounced んが)きみのこと
すきにな(た?)たなら
もしきみが(pronounced んが)ぼくのこと
すきにな(た?)たなら
いつもぼくの こころのなか(て or で)
わらいかけてる あのかわ(い/いい)こ
やくそくしお(を?)あいのこえ(だで or たて)
ことりのよな す(を?)つくろ(を/ほ(?))
もしぼくが(pronounced んが)きみのこと
すきにな(た?)たなら
もしきみが(pronounced んが)ぼくのこい
し(っ?)たらどしおを
まよなかでも こころのなか(て/で)
おしゃべにしてる あのかわ(い/いい)こ
やくそくしお(を?)さみしいときも
やさしくうた(ん?)ひとになの(ほ/を(?))
もしぼくが(pronounced んが)きみのこと
すきにな(た?)たなら
もしきみが(pronounced んが)ぼくのこい
し(っ?)たらどしおを
ふたりでき(つ?)し(お/を)
たのしくな(っちゃ(?))るな
ふたりでき(つ?)し(お/を)
き(っと(?))てれちゃるな
ROMAJI:
Moshi boku ga (pronounced nga) kimi no koto
suki ni na (ta? )tanara
moshi kimi ga (pronounced nga) boku no koto
suki ni na (ta? )tanara
itsumo boku no kokoro no naka (te or de)
warai kake teru ano ka wa (i / ī) ko
yaku sokushi o (o ? ) Ai no koe (dade or tate)
kotori no yo na su (o ? ) Tsukuro (o / ho ( ? ) )
Moshi boku ga (pronounced nga) kimi no koto
suki ni na (ta? )tanara
moshi kimi ga (pronounced nga) boku no koi
shi (~tsu? )taradoshi o o
ma yo na ka demo kokoro no naka (te/ de)
osha be ni shi teru ano ka wa (i / ī) ko
yaku sokushi o (o ? ) samishī (i)toki mo
yasashiku uta (n ? ) Hito ni na no (ho/ o (?))
Moshi boku ga (pronounced nga) kimi no koto
suki ni na (ta? )tanara
moshi kimi ga (pronounced nga) boku no koi
shi (~tsu? )taradoshi o o
futari deki (tsu? ) Shi (o / o)
tanoshiku na (tcha ( ? ) )ru na
futari deki (tsu? ) shi (o / o)
ki (tto ( ? ) ) terecha ru na
1. The ( [letter] / [letter] ) is the one I'm doubt the pronunciation between these two letters in the song.
2. The ( [letter] ?) is the one I'm doubtful if it is supposed to be pronounced or not (he pronounced it not clear enough in the song).
3. The ( [letter] / [letter] (?)) is the combination of the two cases above.
P.S.: Thanks for the response