Q: When I was growing up, almost everyone pronounced “pianist” as PEE-a-nist. But these days, even on classical music stations, it’s pee-A-nist. Is this a misguided attempt to avoid saying something that sounds slightly rude?
A: The word “pianist” has been pronounced both pee-A-nist and PEE-a-nist since it showed up in English writing in the early 19th century.
Today, American dictionaries include both pee-A-nist and PEE-a-nist as standard pronunciations, while British dictionaries list only PEE-a-nist.
The earliest example of the word in the Oxford English Dictionary is from the Jan. 5, 1820, issue of the Times (London): “An accomplished Theorist, emphatic Pianist, and elegantly chaste Articulative Vocalist.”
The oldest dictionary we’ve found that includes the term is Noah Webster’s An American Dictionary of the English Language (1828), which gives PEE-a-nist as the only pronunciation.
However, most of the other dictionaries we’ve seen from the 19th and early 20th centuries give pee-A-nist as the only pronunciation.
For example, A Dictionary of the English Language Exhibiting Orthography, Pronunciation and Definition of Words (1861), by Arnold J. Cooley, gives the pronunciation as pee-A-nist.
Similarly, the Etymological and Pronouncing Dictionary of the English Language (1874), by James Stormonth and P. H. Phelp, has pee-A-nist.
A Critical Pronouncing Dictionary (1881), by John Walker, with a 5,000 word supplement by Edward Smith, gives the pronunciation as pee-A-nist.
And a 1904 edition of the Stormonth-Phelp dictionary, updated by William Bayne, also offers only the pee-A-nist pronunciation.
Two of the most important standard dictionaries of the late 19th and early 20th centuries—The Century Dictionary (1889-91) and Webster’s Revised Unabridged Dictionary (1913)—also pronounce “pianist” as pee-A-nist.
However, James Murray’s early version of the Oxford English Dictionary lists PEE-a-nist as the only pronunciation.
Murray included the pronunciation in his June 1906 “Ph-Piper” fascicle, or installment, of A New English Dictionary on Historical Principles, which became the first edition of the OED. (Volume VII of the NED, covering the letters O and P, was published in 1909.)
Interestingly, the “pianist” entry in the online OED, which was updated in 2006, still accents the first syllable, PEE-a-nist, though the vowels are slightly different in the US and UK versions.
Finally, we’ve seen no evidence that prudery has had anything to do with the pee-A-nist pronunciation. A more likely influence may have been the pronunciation of the instrument itself, pee-A-no.
from Grammarphobia http://www.grammarphobia.com/blog/2016/01/pee-a-nist-or-pee-a-nist.html