What are those strange words beside Pinyin in the dictionary?

Since it has been implemented for 40 years, people before 1958 are familiar with this set of phonetic symbols, so later dictionaries still attach Chinese Pinyin for comparison. Pinyin letters are the first set of legal Chinese Pinyin letters in China. Also known as Mandarin Phonetic Alphabet. 19 13 formulated by the unified speech conference, 19 18 promulgated by the Ministry of Education of Beiyang Government. 19 19 released the phonetic alphabet, and the alphabetical order was rearranged. There are 39 letters * * *. 1920, the sea election committee added the letter "ㄜ" to 40 letters. Namely: ㄅㄇヨㄉㄊㄌ, ?ㄎㄏ, ㄐㄑㄒ, ㄓ. The initial phonetic notation was determined according to the unified pronunciation club. Later, based on Beijing dialect, dialects were marked with three letters: Wan, Wu and Guang. 1922 the Ministry of education published the phonetic symbol calligraphy style, which changed the standard phonetic method, abolished the four-corner phonetic method and used standard phonetic symbols instead. Phonetic symbols are characterized in that ancient Chinese characters are selected for letters, and three spelling systems are used for syllable spelling system, which is mainly used to mark the pronunciation of Chinese characters.