Although I get tense when my wife is in a mood, the words ‘tense’ and ‘mood’ have a somewhat different meaning when applied to language!
The tense of a verb is a means of identifying the time at which the verb was, is, would or will be carried out (the word ‘tense’ is derived from the Latin ‘tempus’, meaning ‘time’). Tense can also be used to convey the idea of what might, could, should, or would happen, or have happened.
There are many different tenses that can be applied to verbs, and in Portuguese each tense has its own set of verb conjugations. English verbs are easier to learn, because we tend not to change the conjugations so much. This means that there are fewer words to memorise – we often rely on auxiliary verbs to form the different tenses.
Moods
As well as being divided into tenses, verbs are split into more generalised categories according to the type of tense.
The most common mood is known as the indicative. This just means that the verb is being used in such a way as to give certainty to the action. For example ‘I will walk home’ – there is no uncertainty as to what is going to happen. ‘I walk home every day’ is also in the indicative mood.
The conditional mood requires that some condition be met for the action to become certain. In English, this is achieved using the auxiliary verb ‘would’. So ‘I would walk home’ is in the conditional mood, and so is ‘I would have walked home’.
Other tenses that carry some degree of uncertainty fall under the subjunctive mood. An example of this mood is ‘If I were to walk home...’. The subjunctive mood is not used as often as the others, so it is better to concentrate your efforts on tenses in the other moods first. However, the subjunctive is used consistently by Portuguese speakers, so you will have to at least understand it when you hear it, and eventually take the plunge and try to learn the conjugations (you will be perfectly well understood if you use indicative tenses where you should use subjunctives, but you will sound foreign to a native).
We have already met the infintive, and this is also a ‘mood’. There are actually two tenses that belong to the infinitive mood. The most common one is the one that you have already learned about, and is generally just referred to as ‘the infinitive’, but to be more technical, it is actually ‘the impersonal infinitive.’ The other infinitive is ‘the personal infinitive’ which does not really exist in English, but does in Portuguese (more on that later).
Then there is the imperative mood, which relates to commands or requests (eg. ‘keep off the grass’; ‘leave me alone’; ‘follow the signs’).
Sometimes, different tenses belonging to different moods can have the same name. Where this is the case, the tense is identified by the name and the mood together. So the present subjunctive is a different tense to the present indicative – both dealing with the present, but one that carries a degree of uncertainty (subjunctive), and one that is definite (indicative). If a tense that can be used in more than one mood is referred to without specifying the mood, the more commonly used tense is assumed (this usually means the indicative mood).