Strong nouns are those which do not become plural by the addition of the sound 's' or 'es' in the plural. The plurals of nouns such as 'mouse' 'sheep' 'narcissus' and 'ox' are 'mice', 'sheep', 'narcissi', and 'oxen'. These are all examples of the few remaining strong nouns in English. Speculation has it that these items will eventually follow the trend in which strong becomes weak. Lexical change .
Vocabulary changes much more rapidly than does the grammar of any language.
Grammatical changes have occured during the course of centuries, whereas a new word phrase or lexical form may enter the language during a matter of only weeks. This is because of the relatively superficial significance of lexis compared with the radical function of grammar in a language. Grammar is the basic working system or structure , and as such must remain constant for the perpetuation of the language. Language as a system is very efficient at adapting to new circumstances and incorporating new phenomena. For instance, information technology has recently developed very rapidly.