Icons and ideographic symbols developed by primitive people are the prototypes of modern letters, such as cuneiform and hieroglyphics. The earliest alphabet is an early hieroglyphic combination used by the Semitic people in the East (known as the northern branch of Semite in modern classification), which appeared between 1700 BC and 1500 BC. In 1000 BC, there were four other kinds of letters, which developed from the letters of the eastern Semitic people, the letters used by the southern branch of the western Semitic people (called the southern branch of the Semitic people in modern classification), the Canaanite letters, the Aramaic letters and the Greek letters. Around 500 BC, the Roman alphabet evolved from the Greek alphabet. By 20 15, all languages in western Europe (including Irish, Dutch, French, German and other languages) will use this alphabet. It is the smallest writing unit of pinyin characters or phonetic symbols.
When the letter combination er appears in unstressed syllables, American sounds are pronounced as weak vowels/? /,such as:
Sister, sister
Ladder ladder
Hammer. Hammer.
Alphabetic letters
Butterfly butterfly
Butter butter
Mother, mother
Dinner, dinner, dinner
I hope it can help you solve the problem.