Complex sentence: Northeastern dialect is very similar to the Beijing dialect, upon which Standard Mandarin Chinese (Putonghua) is based, although many Northeasterners claim to speak a more pure form of Mandarin than those in China's capital.
Split into simpler sentences: Northeastern dialect is very similar to the Beijing dialect, upon which Standard Mandarin Chinese (Putonghua) is based. Although, many Northeasterns claim to speak a more pure form of Mandarin than those in China's capital.