Complex sentence: Since the 14th century, some form of Mandarin has served as a national lingua franca, and in the early 20th century, a standard form based on the Beijing dialect, with elements from other Mandarin dialects, was adopted as the national language.
Split into simpler sentences: Since the 14th century, some form of Mandarin has served as a national lingua franca. In the early 20th century, a standard form based on the Beijing dialect, with elements from other Mandarin dialects, was adopted as the national language.