There are rules for the plurals of regular nouns and the -s forms of regular verbs.
When there is a prefix, we do not normally add or take away more letters:
Words in English are not always spelled as they are pronounced. Spelling in English follows some basic rules and the majority of English words (around 75%) follow these rules. You can learn the rules but there are always exceptions to the rules that need to be learned too.
The main basic spelling rules of English relate to: prefixes and suffixes; spelling and plurals; doubling letters; dropping and adding letters; verb forms. This section focuses on British English but also covers some basic differences in spelling between British and American English.