What you can say to whom
CEFR C1
“Si hubiera sabido…”: the past that did not happenThe unreal past: “si hubiera sabido, habría venido”, and the mixed conditions where one…“Por más que lo intente”, “a fin de que sepas”The conjunctions that always take the subjunctive —“para que”, “a fin de que”, “sin…“Por” and “para”, the hard halfThe pairs where both are possible and the meaning changes: “estar por” against “estar…“Ponerse”, “volverse”, “hacerse”, “quedarse”: four “become”Choosing among the four: “ponerse” for a passing state, “volverse” for a lasting change…What people write and what people sayWhat changes between the two: the “ser” passive, “cuyo”, the tenses that survive only in…“Me alegro DE que” but “pienso QUE”Deciding whether a verb or an expression needs “de” in front of “que”: “me acuerdo de…The rule, in three lines
The same idea has three levels: a message to a friend (¿te va bien a las 8?), an email to somebody you do not know (¿le vendría bien a las 8?) and a written report (se propone celebrar la reunión a las 8). And there are markers that give each level away: vale, o sea, en fin, un montón on one side; le agradecería, no obstante, cabe señalar on the other.
The usual slip. Writing everything at one flat level: a job application with un montón in it, or a message to a friend that reads like a legal notice.
Why it catches you out. You already do this in English without thinking, which is exactly the problem: the markers do not transfer, so your Spanish sits at one level while your English moves freely. And the register words are precisely the ones textbooks skip.