Why Is the Subjunctive Used Here?

From the mailbox:

We are a group of five who meet without a teacher and struggle through books, telenovelas, etc., on our own. We are reading Isabel Allende's La Ciudad de las bestias. We have run into some subjunctive use we cannot figure out.

Alex se colocó junto a su amiga y procuró calmar a los guerreros con gestos, pero lo único que consiguió fue que Tahama cogiera a Nadia por el cabello y empezara a darle tirones, arrastrándola hacia la catarata mientras Borobá daba manotazos y chillaba.

Le repitió lo que tantas veces oyera decir a su padre: «antes de vencer la montaña hay que aprender a usar el temor».

Why is the subjunctive used in these two sentences? Any and all help appreciated. I have posted this to the forum but perhaps you can help too. ¡Gracias!

What an interesting question!

First of all, let me translate parts of your sentences for others reading this:

• ... pero lo único que consiguió fue que Tahama cogiera a Nadia por el cabello y empezara a darle tirones...
  ... but the only it accomplished was that Tahama grabbed Nadia by her hair and began to yank on her ...
• Le repitió lo que tantas veces oyera decir a su padre ...
  He repeated to her what he had so often heard his father say ...

One answer I could give you — and it may sound like a copout — for the first selection is that the phrase "lo único que consiguió fue que" is, as a rule, followed by a verb in the subjunctive mood. The Spanish equivalent of "the only thing it accomplished" is fairly common, and you can simply count on it being followed by a verb in the subjunctive mood. That's quite a specific rule, but it seems to hold true.

But more broadly — and we're getting into some obscure rules of grammar here — is that when a value judgment is expressed by a phrase that begins with lo, a verb in the subjunctive can follow even if it is speaking about an actual event. Here are a few examples:

• Lo normal es que España no gane. The normal thing is for Spain to lose.
• Lo importante es que hiciera un buen trabajo. The important thing is that she did a good job.
• Lo bueno es que comieras a las siete de la tarde. The good thing is that you ate at 7 in the evening.

Although the indicative mood is more common in such sentences when speaking of a past event (so the indicative would have been fine and even preferred in the second and third examples), some speakers do use the subjunctive mood and it is not considered wrong. Your first example fits in this category even if it's a bit more complex than my sample sentences.

Edited in response to the comment by Robert L. Davis below: In my original answer, I stated that I didn't know for certain why the subjunctive mood is used in your second example. But a comment below has pointed me in the right direction.

The fact is that oyera in your example isn't a verb in the subjunctive mood at all — it's actually an old indicative verb form.

The verb form relates to the question of why there are two forms of the imperfect subjunctive. It wasn't always that way. The -ra verb form was originally used as an indicative pluperfect. But languages change, and eventually the -ra form acquired a subjunctive meaning, becoming for all practical purposes a preferred form of the subjunctive over the -se form. But it is still possible in literary styles (not everyday speech) for the -ra form to be used as a substitute for the pluperfect (although it is done only in relative clauses following que). Thus, as Davis stated, a good translation for the sample sentence is "He repeated to her what so often he had so often heard his father say."

This isn't something you need to know for everyday conversations, but now that you know it you'll notice it every now and then literature.

Incidentally, the -ra form sometimes also is substituted for the conditional tense with a few verbs such as poder, querer, deber and haber. In some areas, it isn't uncommon to say something like "Quisiera un café" when ordering a cup of coffee, for example, its literal meaning being "I would want a coffee."

In real life, not every grammatical usage fits into neat categories, and it is not uncommon even for many well-educated speakers to be inconsistent in their use of verb mood. The use of the subjunctive mood often is more flexible than the grammar books (and this site) may suggest.