But God had more for us and this more we could never have known unless God had opened His mouth, as it were, and spoken in words. The animals, along with the inanimate creation, glorify and praise God, but He wanted that and more, thankfulness, to come from us consciously and voluntarily. Mankind was made for friendship with God and friendship requires communication. He desires our love and love requires not only communication, but also loyalty. So in marriage, true love trusts one's spouse even in the face of possible contrary evidence.
Love thinks no evil.
For all this, for fellowship and love, to provide the soil for loyalty to grow and blossom, God had to speak to us verbally. For this, speaking to us indirectly through nature was not enough. On the other hand, it has also to speak to us of God's judgement. So that fruitfulness only comes by hard work, battling the elements and with thorns and thistles and everything else that goes wrong in the world. But God has never forgotten why He spoke to us verbally in the first place.