The noted Evangelical scholar Millard Erickson in his God in Three Persons book makes my point:
"We have said...that God is three and that he is one, and that his threeness is with respect to a different aspect than his oneness. How can we grasp the referents of these terms? How can we ascertain that they really refer to anything objective?"
"It may also be necessary, in order to convey the unusual meaning involved in this doctrine, to utilize what analytical philosophers would term 'logically odd language.' This means using language in such a way as intentionally to commit grammatical errors. Thus, I have sometimes said of the Trinity, 'He are three,' or 'They is one.' For we have here a being whose nature falls outside our usual understanding of persons, and that nature can perhaps only be adequately expressed by using language that calls attention to the almost paradoxical character of the concepts."