Sing Happy Birthday to your favourite programming language

LOLCODE: 109 (105 with "correct" spelling)

LOLCODE is not a great language for golfing, especially since you lose all the beauty and expressiveness when shortening the code.

HAI
H R "HAPPY BIRTHDAY "
T R SMOOSH H "TO YOU"
VISIBLE T
VISIBLE T
VISIBLE SMOOSH H "DEAR LOLCODE"
VISIBLE T

Test it using loljs

This is my preferred rendition, weighing in at 187 characters (spaces added for clarity):

HAI
H R "HAPPY BERFDAY "
IM IN YR LOOP UPPIN YR N TIL BOTH SAEM N AN 4
  VISIBLE H!
  BOTH SAEM N AN 2, O RLY?
    YA RLY
      VISIBLE "DEER LOLCODE"
    NO WAI
      VISIBLE "2U"
    OIC
IM OUTTA YR LOOP
KTHXBAI

Mathematica- barcode birthday wishes--way too many bytes

This prints the verses and reads them aloud.

Happy Birthday to You
Happy Birthday to You
Happy Birthday Dear Mathematica
Happy Birthday to You

StringReplace replaces each comma with a NewLine. Barcodes cannot contain control characters.

TI-Basic, 53 bytes

Well, since everyone is putting their favorite programming language up, I might as well add one of my old favorites. I spent a lot of time over the years (before I graduated to actual programming languages) typing commands into a window half the size of a smart phone.

"HAPPY BIRTHDAY TO YOU
Disp Ans,Ans,sub(Ans,1,15)+"DEAR TI-BASIC
Ans

My calculator doesn't support lowercase letters, and the only variables that can be strings are Str1, Str2 etc.