In Latin, remember that the plural of me is us, and that the plural of us is I. So a double plural is a singular, but you go from the objective to the subjective case.
‘You and I’ would be the subject for the clause, and hence take the subjective case.
Definition of subjective case in US English:
subjective case
noun
Grammar
The nominative.
〔语法〕主格
Example sentencesExamples
In Latin, remember that the plural of me is us, and that the plural of us is I. So a double plural is a singular, but you go from the objective to the subjective case.
‘You and I’ would be the subject for the clause, and hence take the subjective case.