I’ve always thought Samhain was pronounced ‘SAH-when’ or ‘SOW-en’, but recently (and even a couple of decades ago – on The X-Files, I think) every time I hear it in a TV show or movie it is pronounced ‘Sam Hayne’.
Have I been mispronouncing it for more than half my life?
Your pronunciation is correct, altho’ Google shows several ways to say it.
Scott Gaelic will often sound like “samhuin”, Irish Gaelic sometimes sounds like “sow-in” but I don’t know if some other form of Gaelic will be close to “Sam Hayne”
I learned it from people who spoke Connemara Gaelic.
That specific is way past my pay grade, the Halloween movies are wrong though.
It’s an Irish word. (Samhuinn is the Scots Gaelic equivalent.) SOW-in or SOW’n is a close enough approximation to the pronunciation. There’s a mild regional variation - in the north of Ireland the vowel in the final syllable is more likely to be voiced.
I have occasionally heard “Sam Hain”, always from US speakers, who I assumed were simply trying to apply the rules of English orthography to an Irish word that they had never heard spoken. That rarely works out well.
I only heard fictional US sources, I didn’t see the X-files, but I think cartoons like The Real Ghostbusters and other sources went Sam Hayne, and I always pronounced it that way, in my head, when I read it in stories.
'Course, once explained, its obvious that the Gaelic word would be pronounced totally differently. But I did think it was an ancient English word that predated the Christian era. So … ordinance fought. Unless … I’m correct, and it was something like Sam Hayne in English?
There are those who wish that when Gaelic orthography was codified, there was an attempt to make it even slightly phonetic in English. I am one. I don’t know what the point of making spelling so bizarrely difficult. I mean I excuse the French because they probably spell things that way to deliberately make English speakers sound stupid … oh I guess the Irish may carry a small grudge too.
Gene Simmons pronounced it “SOW-in” last night on Jeopardy!, for what that’s worth.
Ok… so the pronunciation is established.
How did they get from Sow-inn/SOW-in to spelling it “Samhain”?
Sure, and Spanish speakers wonder why English and French do not actually pronounce half the letters they use and do so differently from one page to the other. But we should not hold it against the Gaels, Franks, Saxons, Angles and other assorted groups that they mcguivered the Latin alphabet as best they could to fit the people’s speech. By the time it got to them the actual Romans were no longer around to correct them (sure, they could have had also the foresight to add more spare letters, but hey, hindsight).
But really why should a language not directly related to English seek to coincide pronunciation with English.
In Irish, the letter “h” is used to soften the letter that precedes it.
The Irish language uses “initial mutations”, in which words undergo a change in spelling and pronunciation, depending on what comes before. For example, the word for “good” is “maith”, pronounced “maw”, with an aspiration at the end (kind of like the second “h” in “huh”). But, after certain words, the word is pronounced “waw”, with an aspiration at the end, and is spelled “mhaith”.
But wait … it gets weirder. In the case of an “m” followed by an “h”, the pronunciation of the “mh” is further dictated by the vowel that follows. The general rule of thumb is that if the vowel that follows is a “broad” vowel (A, O, or U), then the “mh” is pronounced as a “W”, but if it is followed by a “slender” vowel (E or I), then the “mh” is pronounced as a “V”. (That’s the general rule, but there are 3 main dialects in Irish, and the pronunciations can change, depending on the region.)
To answer bump’s question more directly, when Irish orthography was being developed, the monks made up the rules for transcribing the sounds of the words into a written form. I’m not sure exactly why, but they did not use the entire Latin alphabet, and only chose to use 18 letters, but with those letters and the use of “h” as the softener, they were able to reproduce all the sounds of the language.
Also, it isn’t just Irish that seems weird. In English, there are thousands of words that don’t appear to follow whatever rules you think they should. Consider words with the “-ough” ending and all its variations: lough, slough, through, thorough, plough, cough, etc.
I’ve been studying Irish for 4 years now and am absolutely hooked! I’m not sure why. Even though I live in the USA, I am currently going through the study guide for the O-Level “Leaving Certificate” in Irish, which Irish high-school students take at the end of the last year, similar to the SAT or ACT in the USA.
Which is why I never learned Gaelic when I had the opportunity. I couldn’t get past the spelling. There was one word that was spelled something like ‘claidhmaigh’. It was pronounced ‘clive’.
Actually, there were a number of additional letters used in early English. Look up wynn, yogh, eth, and thorn. They just didn’t survive in English, although some (if not all) have in other languages such as Icelandic and Faroese. I suspect we can blame the Norman invasion for the loss of these additional letters. The dominant French speakers didn’t understand them, so they went away.
Irish and Scottish spelling is reasonably phonetic, certainly compared to English. So is hanyu pinyin. If one does not recognize Samhain as an Irish name (and know the rules) then there could potentially be some confusion (say with a guy named Saerbhreathach signing a hotel register in Astana), but Samhain seems like it would usually come up in a Celtic context.
“Fictional US sources” are not authoritative pronunciation guides 
Re. old pronunciations, Wiktionary says samain/samhain = /ˈsaṽinʲ/ while admitting “some details of Old Irish phonetics are not known”. ṽ has “no English equivalent; like v but nasalized”
Are we pronouncing SOW as in “sow the wheat” or “the sow had 8 piglets” ?
Like a pig. ‘Sau’.
For a trivial fun fact, the use of “Ye Old <whatever>” stems directly from the original use of the thorn character (Þ). It was originally spelled “Þe Old <whatever”, with the “Þ” being pronounced like “th”, so the same as “The”.
Eventually Þ ended up looking a lot like “Y” in certain printing formats, and we ended up with “Ye Old <whatever>”.
English orthography is the least phonetic of all European languages. Why should any other language’s orthography be constructed for the benefit of English speakers? How about making English easy to pronounce from the point of view of Italian or Spanish first?
The fact is that Irish spelling is quite logical for the Irish language. If people can learn English with its inconsistent spelling, it’s really not that hard to learn Irish or French, which are both far more consistent than English.
Here’s another:
The “gh” in “F” sounding words like “enough” is because the words typically had a sort of guttural ‘gh’/‘ch’ type sound like in “loch” or “Bach”, represented by the letter “Ȝ” (yogh). Eventually French scholars started replacing it with “gh”, and then sometime later, the pronunciation changed to more of a “F” sound, but the "gh"s were left behind, leaving us with “enough” or “night”, oddly enough.