How do “verbos auxiliares” complement the use of the subjunctive mood in Spanish?

Question

I have learnt that the subjunctive mood is used extensively in Spanish to express desires, wishes, and uncertainty.

According to this webpage by Durham University, similar meanings are expressed in English using modal verbs. Examples include could, should, would, may, might and shall. The subjunctive mood is only used to a small extent in formal writing.

However, it seems that Spanish uses perífrasis verbales or verbos auxiliares, which are equivalent to the English modal verbs. I find this confusing; if Spanish can express uncertainty using a whole system of the subjunctive mood, what is the purpose of these modal verbs? Perhaps they do not directly correspond to the concept of modal verbs in English?

Answer 1

Spanish doesn't have a distinct class of modal verbs. That is a typically English (or rather Germanic) grammatical feature. English modal verbs are characterized by a defective conjugation ("I can, you can, he can", not "he *cans"); nothing like this happens in Spanish, where verbs like poder and deber are conjugated normally, albeit with some irregularities.

On the other hand, verbal periphrases are found also in English ("be going to" is one of them); these do have parallels in Spanish. "Periphrasis" just means "turn of phrase", in linguistics, "expressing a simple concept using a whole phrase". So English passive voice is periphrastic too (the verb "to be" plus the past participle), and Spanish has both a periphrastic passive voice and another type (the so called reflexive passive or pasiva refleja).

Auxiliaries are also found in both languages, but Spanish only uses one, the verb haber, for the compound tenses, while English uses have for the compound tenses and also will for the future (one could argue that would is an auxiliary too; "auxiliary" and "modal" are not mutually exclusive).

Spanish has a smaller range of "modal" verbs (basically poder and deber), but all verbs including these two can appear in the subjunctive mood, or they can be conditional (roughly an equivalent of using English would). So what English expresses using modal verbs, Spanish shows by using poder, deber, some equivalent turns of phrase that refer to ability and obligation, and the contrast between the conditional, the plain indicative and the subjunctive. You have to study it without reference to English, because the two systems don't match, although of course translation is usually possible.

In general the English -ould auxiliary/modals translate to conditional verb conjugation in Spanish:

• "he does" = hace
• "he would do" = haría
• "he could do" = podría hacer
• "he should do" = debería hacer

The subjunctive is too complex a topic to deal with in a general question. The old English subjunctive is largely moribund ("he requested that she be buried next to him if she were to die before him") and Spanish subjunctive is applicable to many kinds of statements.

Answer 2

This is a very broad question, but the answer is mostly that we use the subjunctive to express some things (desires, wishes, uncertainty), and we use perífrasis verbales to express other things. If you check the examples on the website you link, you will see that most of the places where we use subjunctive in Spanish are actually translated as indicative (or infinitive) in English, without any modal verb:

• No creo que esto sea muy sencillo (I do not think this is very easy)
• No voy a permitir que me insulten (I am not going to let them insult me)
• Ponlo donde quieras (Put it wherever you want)
• Si llegara a tiempo, se divertiría (If he came in time, he would have fun) (although in this case, would come, with a modal, is also fine)

If you go over the list of modal verbs that you provided, you will see that those 6 modal verbs (or 5, depending on whether may and might are the same verb or not) are (roughly, usually) translated as only 2 in Spanish:

• could, may, might -> puede/podría
• would -> conditional tense (no modal verb)
• shall -> present or future tense (no modal verb)
• should -> debería

So we definitely use verb tenses in some cases where English would use modal verbs. But our subjunctive is usually translated as verbs with no modals in English.

On the other hand, our perífrasis verbales are used to express other ideas, such as

• intention in the near future: Voy a comer (I am going to eat)
• a recently finished action: Acabo de comer (I have just eaten), or Vengo de comer
• and many, many others.