Words, like cliffs, erode over time. Latin mea domina ‘my lady’ changed to French ma dame. French ma dame became madam. Madam has become ma'am, and even 'm, as in Yes'm. Words with lexical content empty out, then get attached to others. The word full as in ‘a basket full of apples’ has became a compound, as ‘a spoonful of sugar’, and also an affix, as in hopeful. Similar examples can be found in almost every sentence.

This pruning-down process is known as grammaticalization or grammaticization, a term coined by the French linguist Antoine Meillet, who defined it as ‘the attribution of a grammatical character to a previously autonomous word’. The process is allpervasive. ‘Grammaticalization … is in fact probably the source of the majority of grammatical changes that languages undergo’, it has been claimed.