No one added their own words to the title. For example, the name of Emperor Wu is Song. It was someone else who added a surname to the song of Emperor Wu of Song to distinguish it from the previous dynasty and became Liu Song.

Tang, Song, Yuan, Ming and Qing dynasties need not be distinguished by surnames.

Tang: Li Yuan succeeded Tang Guogong. So take Tang as the country name.

Song Dynasty: After Zhao Kuangyin was appointed as China's ambassador to Germany in Songzhou, he took the word "Song" in Songzhou as his country name.

Ming: From Zoroastrianism.