Bothsoyandestoymean 'I am'. However, there are some differences regarding their usage. Soy(whose infinitive isser) means 'I am', and it is used... Learn more about this topic: Ser vs. Estar in Spanish | Conjugations, Examples & Uses ...
This solution can account for the attested chronology of the change (so soy significantly predates the other changes). Two largely independent regional developments in Castilian and Leonese provide contrasting multi-stage diffusion patterns for affecting the closed subset of the four 1s pres ind verb...