Should you be arrested, you will be allotted the free services of an abogado de oficio (duty solicitor), who may speak only Spanish. You are also entitled to make a phone call. If you use this call to contact your embassy or consulate, it will probably be able to do no more than refer you to a lawyer who speaks your language. If you end up in court, the authorities are obliged to provide a translator if you have to testify.
In theory, you are supposed to have your national ID card or passport with you at all times. If asked for it by the police, you are supposed to be able to produce it on the spot. In practice it is rarely an issue and many people choose to leave passports in hotel safes.
There are three main types of policía: the Policía Local, the Policía Nacional and the Guardia Civil. Should you need to contact the police, don’t agonise over which kind to approach: any of them will do, but you may find that the Policía Local is the most helpful. The Canary Islands government provides a toll-free telephone number (112), which ensures that any emergency situation can be attended to by the nearest police available.
Spanish law defines any individual under the age of 18 to be a minor.