While girls and women call themselves 私（わたし or わたくし）most of the time (apart from regional variations),  men call themselves differently.

• 私（わたし or わたくし）- formal
• 僕（ぼく）- boys use this first and later learn to use other words as they grow up
• 俺（おれ）- young men often use this in casual speech.
• わし – older men sometimes use this in casual speech.