Основні сполучники

A handful of short words join your sentences together. Most map neatly onto English; two have a sound-based spelling change, and Spanish has two words for "but".

Y becomes e, o becomes u

Two vowels of the same sound would merge in speech, so Spanish changes the conjunction:

• y → e before a word starting with the sound "i", spelled i- or hi-: español e inglés, madre e hija, Fernando e Isabel. Not before hie-, which sounds like "ye": agua y hielo.
• o → u before a word starting with the sound "o", spelled o- or ho-: siete u ocho, mujer u hombre, ayer u hoy.

Pero or sino?

Both are "but", and they do different jobs:

• pero adds something that contrasts: Es caro, pero es bueno. No hablo alemán, pero lo entiendo un poco.
• sino corrects a negative statement, replacing what was denied: No es rojo, sino azul. - It isn't red, it's blue. No soy inglés, sino escocés.

The test: if you could say "not X but rather Y" or "not X, it's Y", it is sino. If both halves are true at once, it is pero.

Que: the "that" you cannot drop

English often leaves out "that": "I think (that) it's late". Spanish keeps it: Creo que es tarde. Dice que viene mañana. *Creo es tarde is not possible.

Porque and por qué

"Because" is one word without an accent, porque. The question "why?" is two words with an accent, ¿por qué?: - ¿Por qué estudias español? - Porque quiero vivir en Barcelona.