According to Guy Deutscher, the tricky question is "Why are changes not brought up short and stopped in their tracks? At first sight, there seem to be all the reasons in the world why society should never let the changes through." He sees the reason for tolerating change in the fact that we already are used to "synchronic variation", to the extent that we are hardly aware of it. For example, when we hear the word "wicked", we automatically interpret it as either "evil" or "wonderful", depending on whether it is uttered by an elderly lady or a teenager. Deutscher speculates that "n a hundred years' time, when the original meaning of 'wicked' has all but been forgotten, people may wonder how it was ever possible for a word meaning 'evil' to change its sense to 'wonderful' so quickly."
The ongoing influx of new words into the English language (for example) helps make it a rich field for investigation into language change, despite the difficulty of defining precisely and accurately the vocabulary available to speakers of English. Throughout its history English has not only borrowed words from other languages but has re-combined and recycled them to create new meanings, whilst losing some old words.