1. Go to the nearest tourist Police boot and ask them to assist you with the translation (YES, I have done that before a few times and the answer was YES every time).
2. Talk with the Motorbike driver and see if you can settle the case in a decent way.
3a. The case can be settled reasonnable, do it and ask signed papers of the settlement.
3a. The motorbike driver makes unreasonable demands or is unwilling to settle the case, seek advice from a lawyer and let the lawyer handle the case.