The Tone Spectrum

English runs on a spectrum from formal to casual, and each level has its own markers:

• Very formal: "I would be most grateful if you could..." — legal, diplomatic, or executive
• Professional: "Could you please send me..." — standard business tone
• Friendly professional: "Would you mind sending me..." — warm but appropriate
• Casual: "Can you send me..." — friends, close colleagues
• Very casual: "Send me that" — close friends, texting

Most learners use one tone for everything. Keep at least three registers ready: formal, professional, and casual. Shifting between them is called code-switching, and native speakers do it without thinking.