Laton in Spanish means brass - most likely a high zinc content on the base metal.
LATEADO most likely is the Mexican City of Plateado...you will find pieces marked with this and most often the P is missing or worn.
Most likely this is Alpaca silver...since it isn't marked with the regular silver marks. Alpaca silver isn't in fact silver, but has the look of silver and more durable. It is very popular in S America and Mexico...thus it is marked Laton.