Based on the context, it seems David wrote these words to close one Psalm 19, one of my favorite Psalms, with a prayer to the almighty God. He was hoping the words he just wrote would be pleasing to the creator of the universe.
When this verse is considered in isolation, it seems to be simply a prayer. As if this verse is just a poetic way to close out a Psalm.
There is a richness in the text, though, that isn't apparent until the first four verses of the Psalm are considered:
David is closing the Psalm that began with his description of the voice of all creation pouring out praise to God. This makes me wonder if he is comparing his words, on a human basis, to the wonder of creation and realizing how meager they look when compared to a sunrise.
God's handwriting is so big and so bold we should delight in it. Our words are insignificant in comparison and yet we think them terrifically important. We rarely stop to consider whether they are worth anything, as special as we think they are. Maybe we need to rethink our perspective.
We should certainly talk to God and often. However, it seems we should recognize the limitations of our own speech in light of the grandeur of his creation.
There is resonance between this Psalm and the scene in the book of Job where God demonstrates his power by showing Job what he has created (Job 38-39). Job then responds:
This is part of the purpose of nature, what theologians call general revelation. It points us toward God's greatness and should drive us toward humility.