manual alphabet

例句：

1. 1. The manual alphabet is a system of writing that relies on the use of letters and symbols instead of numbers.
   手动字母表是一种依靠使用字母和符号而不是数字的书写系统。
2. 2. In the manual alphabet, each letter has a specific sound and meaning.
   在手动字母表中，每个字母都有特定的发音和含义。
3. 3. Manual alphabets are often used in countries where literacy rates are low, as they require no knowledge of numbersor computers.
   手动字母表通常在文盲率较高的国家使用，因为它们不需要了解数字或计算机知识。