Generally speaking, this includes friends, most classmates, most children, and most siblings or younger cousins. Avoid using this with anyone who has a higher status than you, such as a teacher, supervisor, stranger, or elder.
[header] How to say happy birthday in japanese [title] Tell friends " tanjoubi omedetou. [step] " this is a casual, informal way of telling someone " happy birthday. " [substeps] Only use this expression with people you are familiar with and those whom you are able to speak informally.