Pronunciation of "-thwaite"
Planning a trip to Huddersfield the other day, I happened across the nearby villages of Linthwaite (pronounced lin-fit) and Slaithwaite (pronounced slow-it, or slaw-it depending who you ask). Thinking this strange I looked into the matter and turned up Seathwaite (pronounced sea-wait), and also Bassenthwaite and Hawthornthwaite, pronounced as you would expect. I have been unable to turn up any guide as to how Haverthwaite, Hampsthwaite or Thornthwaite are pronounced.
I realise that the pronunication of place names surpasseth all understanding, but my question is, are the three odd pronounciations the remains of an older form? If so, how came their names to be spelt that way? And if not, is there any reason those particular names are corrupted and not others?
I suspect it isn't just a matter of local accent as Seathwaite is quite a way from Slaithwaite and Linthwaite (which are quite close together). Is there perhaps an isogloss for this?
The OED says that thwaite is from
Old Norse þveit, þveiti a piece of land, a paddock.
According to this article on the pronunciation of Old Norse, þveit would have been pronounced [θvεɪt]. The change from [θv] to [θw] is a natural articulatory simplification, and it looks as if the Great Vowel Shift would have changed [εɪ] to [eɪ].
Another pronunciation of —thwaite is [θεt]. William Dickinson's 1829 A glossary of the words and phrases of Cumberland, page viii, says:
Seathwaite in Borrowdale is pronounced as Sea-thwaite or -whate, while Seathwaite on the Duddon is Seäthet—the e and a in sea being distinct. Calthwaite near Penrith, and Scothwaite near Ireby, are both pronounced as o long—Cothet and Scothet.
I think this makes it very implausible that there was an older pronunciation shared by Cumbria and Yorkshire other than [θwεɪt] or [θweɪt] (what else could it have been, given that we need to explain the variety of modern forms?), but I suppose it's possible that the Yorkshire group of pronunciations ending in [ɪt] indicate the former existence of a local pronunciation like [θwɪt]. But this is just a guess. The question doesn't seem to have been studied.
As Gareth Rees says, all of the pronunciations of -thwaite mentioned in the question seem like they can be explained as developments from a common form that more or less corresponded to the spelling. Place names often undergo phonetic simplifications that are more extreme and irregular than the sound changes that affect regular words.
"Reduction" of unstressed vowels is such a common sound change in English that I don't think the use of /ɪ/ in some place names ending in -thwaite needs any special explanation.
The consonant changes look more unusual, but I don't think they are inexplicable. The sound /w/ has often been dropped in unstressed syllables: some other examples of this are certain place names ending in -wich, the word answer, and (according to my research) the word conquer. This seems like it would explain the pronunciations ending in "thet" that are described in Gareth Rees' answer and dads' answer.
I'm not sure about how to explain the pronunciation "Linfit". I see two possible explanations:
The /f/ seems like it might be due to coalescence of /θw/ to /f/: the sound /f/ is a labiodental fricative, and has some phonetic similarities with both the sound /θ/, a dental fricative, and the sound /w/, a bilabial approximant. Possibly this passed through some intermediate lenited stage like /hw/ or /ʍ/—Gareth Rees's answer says that "-thwaite" may be pronounced "-whate" in some place names, and there are other examples of the "wh" sound changing to a "f" sound (Wikipedia says that a change of /ʍ/ to /f/ occurs in some Scots dialects and in some Irish English accents, but I would guess that it could show up in other places as a sound change affecting a proper name like this).
Another possible explanation might be loss of /w/, followed by fronting of /θ/ to /f/. Wikipedia says "th-fronting" is a feature of "some West Country and Yorkshire dialects" so it seems like this sound change could be relevant.
Just to add to Gareth's answer my dad knows the Borrowdale locals very well since the 50's. I even had a pronunciation lesson off one of them in the back bar at Rosthwaite, forgotten his name but he set up charges in quarries and had lots of pet snakes! These are the ones I remember.
- Seä-thet
- Sty-an-thet or Styn-thet
- Ros-thet
And
- Sawfell not Scarfell