What is the difference between the indicative, and the subjunctive?

First of all, it is important to understand that the indicative and subjunctive are both moods. This is something that reflects a speakers attitude towards a statement. The indicative mood is used towards factual statements, that are thought to be true. For example, "Jack speaks English" would translate to "Jack habla español" The verb hablar, is conjugated in the present indicative, as the statement is true.However, if the statement was "It is possible that Jack speaks English", this would translate to "Es posible que Jack hable español" The verb hablar, is conjugated in the present subjunctive, as an element of doubt is implied.