Counting the number of repeated phrases in a column

It is easy to count the number of occurrence of words, but it is rather difficult to count the number of occurrence of phrases.

For instance:

A cell of value:  'Hello World' means 1 occurrence a phrase.

A cell of value: 'Hello World World Hello' means no occurrence of any repeated phrase.

But, A cell of value: 'Hello World World Hello Hello World' means 2 occurrences of 'Hello World'.

'The City of London, London' also has no occurrences of any repeated phrase.

Anyone has got such a function to check out the number of occurrence of any repeated phrases?

Regards,

David