Standard Tibetan (Lhasa dialect):
* བཀྲ་ཤིས་བདེ་ལེགས་སོ། ། (Tashi Delek) - This is a general greeting meaning "Good luck" or "Congratulations," but it's commonly used for birthdays as well.
* སྐྱེས་སྐར་དུས་ཆེན་ལ་བཀྲ་ཤིས་བདེ་ལེགས་ (Kyeskar Dutshen La Tashi Delek) - This translates to "Happy Birthday" literally and is more formal than just "Tashi Delek."
Kham Tibetan:
* ཀ་ཀ་སྟེ་ལེགས་ཤོག (Kaka Te Lek Shog) - This is a more informal way to say "Happy Birthday."
Amdo Tibetan:
* བཀྲ་ཤིས་བདེ་ལེགས་ (Tashi Delek) - Same as standard Tibetan.
Note: Tibetan has different dialects, and the exact pronunciation of these phrases might vary.
No matter which way you choose to say it, the sentiment of wishing someone a happy birthday is the same across all dialects.