When writing a letter to a friend, the tone and style tend to be informal, conversational, and relaxed. You might use casual language, include jokes or personal anecdotes, and express emotions openly. The structure can be more flexible, and you might write in a way that reflects your personality and your relationship with your friend.
In contrast, when writing a letter to a principal, the tone is usually more formal and respectful. The language tends to be polite and professional, with a clear structure that includes a proper greeting and closing. You would likely avoid slang or overly casual expressions, focusing instead on clarity and respect. The content would be more precise, possibly addressing specific issues or requests while maintaining a respectful demeanor.
Overall, the key differences lie in the level of formality, the choice of language, and the structure of the letter, reflecting the nature of the relationship and the context of the communication.