Of course, God can communicate with anyone, but He doesn't. He only communicates with those whom He has chosen.
[Jhn 6:36-37 KJV]
36 But I said unto you, That ye also have seen me, and believe not.
37 All that the Father giveth me shall come to me; and him that cometh to me I will in no wise cast out.
Please, read these verses closely. We are told in them that it is IMPOSSIBLE for natural man (the unsaved), to know or come to faith in Christ, of themselves. Natural man will not take to heart that which he considers foolishness. Therefore, it cannot be by "outward witness", nor by the "wisdom of man" that he learns, but only first by direct intervention and teaching of the Spirit of God. Notice, that it doesn't say by "observing" but by "teacheth". Further, no one can "abide in Him" unless he has first been taught of God.
[1Co 2:13-14 KJV]
13 Which things also we speak, not in the words which man's wisdom teacheth, but which the Holy Ghost teacheth; comparing spiritual things with spiritual.
14 But the natural man receiveth not the things of the Spirit of God: for they are foolishness unto him: neither can he know [them], because they are spiritually discerned.
[1Jo 2:27 KJV]
27 But the anointing which ye have received of him abideth in you, and ye need not that any man teach you: but as the same anointing teacheth you of all things, and is truth, and is no lie, and even as it hath taught you, ye shall abide in him.