This song is a composition of Swami Tejomayananda, Chinmaya Mission.

In Sanskrit

जन्मदिनमिदम् अयि प्रिय सखे
शंतनोतु हि सर्वदा मुदम् ।।

प्रार्थयामहे भव शतायु:
ईश्वर सदा त्वाम् च रक्षतु ।।

पुण्य कर्मणा कीर्तिमार्जय
जीवनम् तव भवतु सार्थकम्

In English

janma-dinam-idham ayī prīya sakhe |
shantanotu te sarvadā mudam ||

prārthayāmahe bhava shatāyushī |
īshvaras-sadā tvām cha rakshatu ||

punya karmanā kīrtimārjaya |
jīvanam tava bhavatu sārthakam ||

Line-to-Line explanation of this song:

अयि प्रिय सखे जन्मदिनमिदम् शंतनोतु हि
ayi priya sakhe, janmadinam idam sham tanotu hi|
hey dear friend, let this birthday bring peace to you

शतायु: भव
satayu: bhava|
let you live 100 years

ईश्वर: त्वाम् च सदा रक्षतु
eshwara: twam ca sarvada rakshtu.|
always, may God protect you also.

पुण्य कर्मणा कीर्तिमार्जय
punya karmana keerthim arjaya|
gain glory through meritorious acts.

जीवनम् तव भवतु सार्थकम्
jeevanam tava bhavatu saarthakam|
let your life be fruitful.

इति सर्वदा मुदम् प्रार्थयामहे
iti sarvada mudam prarthayamhe |
thus we all pray happily always.

Meaning of this song in English: O dear friend! May this birthday bring auspiciousness and joy to you forever. Indeed, we all pray for your long life. May the Lord always protect you. By noble deeds, may you attain fame, and may your life be fulfilled.