Hello and welcome to my newest venture, the start of an online grammar book, to help foreign language students understand how grammar works not only in English, but also how grammatical features operate in German and French. Each grammar point will appear as a regular blog, so please look out for more in future!
The first item I’d like to consider in my new series is the use of apostrophe in English, pronounced /əˈpɒstrəfi/ for those of you familiar with the International Phonetic Alphabet (IPA). Its origin from the Greek απόστροφος - or apostrophos in the Roman alphabet.
So what is an apostrophe? It is a form of punctuation, which as well as other uses not discussed here, indicates a form of the genitive case, specifically the possessive:
i. Singular possession, e.g.
John’s book (the book of John), Sarah’s case
ii. The apostrophe is added to names and words already ending with an –s, e.g.
Thomas’s job, the bus’s arrival
iii. And with plural nouns which end with an –s:
The girls’ shoes (the shoes of the girls), the ladies’ cloakroom, two weeks’ work
See how the apostrophe has moved from ‘s in the singular to s’ in the plural in the first example?
iv. Where the plural does not end in an –s, the following happens:
The children’s toys, the geese’s habitat, the gentlemen’s team
v. A name ending in –s takes only an apostrophe if the possessive form is not pronounced with an extra –s. Hence:
Socrates’ philosophy (we do not say *Socrates’s philosophy), and similarly:
Saint-Saëns’ music
vi. Common errors – there are no apostrophes in pronouns:
She lost her pen, which table is ours, the dog wags its tail
Apart from the exception, one’s:
Even if one’s life depends on it
Also: The government has been criticised for its policy on housing. Here there can be no apostrophe for the pronoun its, as it’s is a contraction for it is or it has, e.g.
it’s raining, it’s gone away
Similarly: You cannot form the plural with -‘s, i.e. *sock’s, *café’s, *pizza’s,
you simply write: socks, cafés, pizzas
Sources
https://www.grammar-monster.com/glossary/genitive_case.htm#exam
http://www.sussex.ac.uk/informatics/punctuation/apostrophe/possessives