Connectors (conectores) join words, phrases or whole sentences. Two of them, y and o, change their form for sound reasons, much like English a book but an apple.
Adding: y / e (and)
y joins things of equal weight: two words, two phrases or two sentences.
Trabajo y estudio.
I work and study.
Un café con leche y un cruasán, por favor.
A white coffee and a croissant, please.
Before a word beginning with the i-sound (spelled i- or hi-, since the h is silent), y becomes e, so that two i-sounds do not collide. The spelling follows the sound, just as English writes an hour.
Hablo español e inglés.
I speak Spanish and English.
Es la relación entre madre e hija.
It is the relationship between mother and daughter.
Exception: before hie- the word stays y, because that syllable sounds like English ye-: agua y hielo.
Choosing: o / u (or)
o offers two possibilities.
¿Quieres té o café?
Do you want tea or coffee?
Salimos el lunes o el martes.
We leave on Monday or Tuesday.
Before a word beginning with the o-sound (spelled o- or ho-, the h again silent), o becomes u.
Tengo siete u ocho libros.
I have seven or eight books.
No sé si es mujer u hombre.
I don't know whether it's a woman or a man.
Contrast: pero / sino (but)
pero sets up a contrast or a limitation, the ordinary English but.
Quiero salir, pero estoy cansado.
I want to go out, but I'm tired.
El piso es pequeño, pero cómodo.
The flat is small but cosy.
Reason: porque (because)
porque gives the reason and takes a full clause, with a subject and a conjugated verb. For a bare noun, English because of the rain becomes por la lluvia.
No salgo porque llueve.
I'm not going out because it's raining.
Estudio español porque me gusta.
I study Spanish because I like it.
The question why is por qué: two words, with an accent. The answer because is porque.
¿Por qué no vienes? — Porque estoy enfermo.
Why aren't you coming? — Because I'm ill.
Time: cuando (when)
cuando links two things in time, for a habit as well as for the past. For the future, English says I'll call you when I arrive with a present tense; Spanish needs the subjuntivo there (more on this later).
Cuando llego a casa, ceno.
When I get home, I have dinner.
Cuando era niño, jugaba mucho.
When I was a child, I played a lot.
