Why English speakers say *buen día* instead of *buenos días*

English greets in the singular: "good morning", "good afternoon", one of each. So English speakers naturally reach for a tidy singular in Spanish and produce buen día. It feels logical, and in most of the Spanish-speaking world buenos días is the expected form — though buen día is perfectly standard in the River Plate region (Argentina, Uruguay). Learn buenos días and you'll be right everywhere.

Spanish greets in the plural: buenos días, buenas tardes, buenas noches. Keep the -s. Think of it as wishing someone many good mornings at once, generosity built into the grammar.

One detail catches everyone: días is masculine even though it ends in -a, so it takes buenos días, not buenas. Tardes and noches are feminine, hence buenas.

A second trap: buenas noches is both a greeting and a goodbye at night, unlike English "good night", which only ever leaves. And in the formal world, say with Señora Ortega, opening with a breezy hola can feel too familiar; a plural greeting is the safer, warmer choice.

• Morning at the café: Buenos días, Rosa.
• Afternoon in the market: Buenas tardes, Don Beto.
• Arriving or leaving at night: Buenas noches.

Say it with me: Buenos días. Buenas tardes. Buenas noches. Always plural, always with that final s intact.