Io sono , loro sono
Sorry for those that speak fluent Italian this is probably the dumbest question they'll ever read. Anyway....in Italian you say for example "io sono..." or "loro sono" right? However quite often i hear sono.... with out the io or loro. How do you know whether its a io or loro. For example if i said sono inglese how would you know if i meant io or loro???
"Sono inglese" is singular, "sono inglesi" is plural, that's how you would know ;)
As mentioned, you will know (or be able to figure it out) by the rest of the sentence which must agree with the subject. It's common in Italian to omit the personal pronoun (unless one is being emphatic or wishes to be extra clear) because the verb endings, in a sense, include that info automatically.