It is obvious that all languages change over time and vary according to place and social setting. So the English language is not an exception

It is obvious that all languages change over time and vary according to place and social setting. So the English language is not an exception. English, from its very beginning in the Anglo-Saxon times to the language that it is today, has come a long way, having been influenced by other languages, religion and social development.
It is interesting to note that the change of meaning of words and expressions happens in every language all the time. Luckily for the speakers, this change usually takes quite a long time, and therefore gives the users of the language the chance to adapt to it. In fact, there is usually a period of time, when the two or more meanings coexist in the language side by side. Semantic widening and Semantic narrowing are very common types of semantic change. For example the word ‘flower’ is a hypernym to a group of co-hyponyms such as ‘rose’, ‘tulip’, ‘daisy’… and others.
Semantic widening, i.e. broadening or generalization of meaning is a process of semantic change that causes a situation where the word’s meaning becomes more general, or as the name suggests: wider – it encompasses more concepts. This type of change results in quite an understandable alteration. The original meaning of the word is still included in the new meaning. There is a couple of examples of the semantic widening in the vocabulary for the animal kingdom. One of them is the word ‘bird’. The very origin of the word is unknown, however, there was one, quite similar word in Old English: ‘brid’. It would stand for a baby bird or a chick. The word for an adult bird used at the time was ‘fowl’, (now still in the language, but with a different meaning see semantic narrowing). ‘Bird’ and ‘brid’ coexisted in English until about the 15th century, from whence on only ‘bird’ remained in the general language. ‘Bird’ was later also used in British slang in association with women. The origin of this association could, however, be traced back to the Middle Ages, when there was the word ‘burd’ used for young women. Thus, it is not certain, from which form the slang use arose. The process of semantic widening also affected the word ‘hound’, which until the Middle Ages was the term naming all the canine animals. Now it refers only to particular breeds of dogs. When it comes to semantic narrowing, semantic narrowing or specialization is a process of meaning change opposite to semantic widening. When a word undergoes this process, its meaning becomes more specific. The new meaning of a word, which has been altered through the process of semantic narrowing, is usually one of the more specific meanings included in the original word. Often, it is the one meaning that is used more frequently than the other meanings or the general one.
Similar is the case of ‘meat’ a word derived from the Old English ‘mete’, which, back then, could denote any kind of meal or food instead of the con-current, much narrower meaning, animal flesh. Semantic narrowing affected also two words related to females. The first one is ‘girl’. Though its origin is uncertain, nowadays we know that up to about 16th century it could refer to a child of any gender. The other word is ‘wife’, which is used in Modern English for a married woman.