Posted by Andrew Crockett
An occasional column that celebrates finer distinctions in the English language
 
enquire/enquiry, inquire/inquiry
 
From the time that enquire/inquire came into English from the Old French enquerre (modern French enquérir) in the 13c. until the early 20c., forms with the initial en- or in- were used with roughly equal frequency with no difference in meaning.  
 
At present, the in- forms are dominant for all senses in American English, whereas in British English there is a tendency to prefer the in-forms for official or formal types of investigation and (to a lesser extent) the en- forms for routine or general types of information-seeking.  The differences in BrE are seen in these typical collocations: (formal investigation) inquiry agency; judicial inquiry; public inquiry; a committee of inquiry; (general information-seeking) enquired after her health; several enquiries about joining the ClubI’ll enquire what time the show starts.  The distinction is, however, still far from absolute.
 
In AmE the noun inquiry is often pronounced with emphasis on the first syllable, i.e. /’inkwiri/
 
In Australian English, we use either spelling although enquire and enquiry for the general sense of ‘ask’, and inquire and inquiry for a formal investigation, is preferred. 
 
Sources: Fowler’s Dictionary of Modern English Usage, Fourth Edition, 2015 and