By intuition; with skill or accuracy, but without special training or planning; instinctively.
(quote-book)
Thus, native speakers have an intuitive knowledge of the syntactic relations between the words in sentences in their language; in other words, they intuitively know how words are combined together to form Phrases, and Phrases are combined together to form sentences. ...
Though he had never been to art school, he intuitively painted vivid landscapes.