A lawsuit based on a dog bite case can be filed a few months after the accident, or more than a year afterwards. It depends on whether the defendant and/or his insurance company are unreasonable about settlement. The discussion of settlement can break down immediately after the victim's attorney makes his first presentation; for example, the defendant might lie about whether he owned the dog, or whether the victim provoked the attack. In other cases, the discussion might be cordial until the full extent of the damage to the victim is known, which could take a year or more. So the lawsuit is not filed until it is clear that the case cannot be settled, and that might take months or more.
Once in litigation, a case takes many more months or even several years to resolve. The major events in a lawsuit are the exchange of written discovery documents, the depositions of the parties and the witnesses, the motion for summary judgment (where the defense tries to have the case thrown out of court without a trial), the mediation, and the trial itself. Not all of these 5 events (or in the case of depositions, groups of events) occur in every case. The events are spread out over two years or more.
Therefore it always is frustrating for the attorneys and parties alike. Nevertheless, there is little that can be done to make it all happen faster. One wants to settle rather than litigate, in order to resolve a case more economically and with less impact on the victim. If a case cannot be settled, it goes into the civil justice system, which was designed for deliberate resolution of disputes, as opposed to just speedy results. It also is a chronically underfunded system, so there are far more lawsuits than courtrooms available to work them out. This is especially true in times of economic shortages. Consequently, one has to be extremely patient and not expect to receive "news" at regular intervals. When substantive events occur in a case, a client will be updated, but at other times one simply has to wait.