"solder" and "salve" phonetics between AmE and BrE

Question

Many will know that there are differences in AmE and BrE pronunciation of the words "solder" and "salve".

On the topic of "solder", there are already two questions here asking about the correct American pronunciation of "solder". Neither of these give a good answer explaining why, but there's at least one anecdote:

This doesn't come from a dictionary, but I had a relative who spent most of his free designing clever circuits (from the 1920s onwards).

He always told me that the correct British pronunciation was "sodder", but that over the years it had started to be pronounced "solder" - which he believed was to avoid the embarrassment of a word that could be misinterpreted as being related to sodomy when speaking to people who didn't have a background in electronics (or pipework!).
Answer by user Tim Wintle

Another answer by caxtontype gives the etymology from Merriam-Webster which suggests the introduction of the 'l' came about later:

Middle English soudure, from Anglo-French, from souder to solder, from Latin solidare to make solid, from solidus solid First Known Use: 14th century
Answer by caxtontype

There's no corroboration of the "sodomy" explanation or perhaps even the expression "sod it".

Regarding "solder", I would like to know if anyone has access to a BrE dictionary from about between 1800 to 1900. That way, if it provides pronunciation we can know whether the 'l' sound was added to "solder" fairly recently in BrE.

Another case of the Americans dropping the 'l' is in "salve":

n
1. (Medicine) an ointment for wounds, sores, etc
2. anything that heals or soothes
Collins English Dictionary

In BrE the pronunciation is given as "sælv" whereas in American the 'l' usually is dropped.

Wikipedia has some extensive information about the very common dropping of the 'l' during the Early Modern English period, that is, roughly the late 1400s to the the late 1600s:

• Words with /alk/ and /olk/, which again followed the same pattern, but also dropped the /l/, so that words like chalk, talk and walk now have /ɔːk/, while folk and yolk rhyme with smoke.
  
• Words with /alf/ or /alv/ (calf, half, halve), which simply lost the /l/ (the vowel of these is now /æ/ in General American and /ɑː/ in RP, by BATH-broadening). The word salve is often pronounced with the /l/; the name Ralph may be /rælf/, /rɑːlf/, /rɑːf/ or /reɪf/. Words like solve were not affected, although golf dropped the /l/ in some British accents.
  
• Words with /alm/ and /olm/, which lost the /l/ and lengthened the vowel (the lengthened [oː] later becoming diphthongized in the toe–tow merger). Words like alms, balm, calm, Chalmers, qualm, palm and psalm now generally have /ɑː/ in the standard accents, while holm and Holmes are homophones of home(s). Some accents (including many of American English) have reintroduced the /l/ in these words as a spelling pronunciation. The word salmon generally retains a short vowel despite the loss of /l/.

...

The /l/ has also been lost in the words would and should.
Phonological history of English consonants

Regarding "salve", I would to know whether the American dropping of the 'l' is a result of the provenance of the British colonists and their accent/dialect. This is because evidently many of these changes didn't occur universally, that is, certain accents or dialects of English underwent certain of these changes during the Early Modern English period, and others didn't. The population of British colonists in 1688 was only 200,000.
Thirteen Colonies

So I would like to know if the explanation of the difference is that this small number of colonists came from English-speaking parts where the 'l' dropping phenomenon happened, whereas the majority of English speakers in Britain spoke English which wasn't affected by this loss of the 'l', and if that explains the current difference.

Edit: Just heard Bill Maher, American comedian pronounce "salve" with an 'L'. Video

Answer 1

TLDR: Middle English spelling shows that the /l/ in solder was not pronounced in Middle English. But early pronouncing dictionaries show that circa 1800, it had started being pronounced in England but not the U.S. For salve, spelling shows the /l/ in calf, half, salve was generally present in Middle English (except maybe in Scotland), and dictionaries show was still being pronounced circa 1800 in England, but not in the U.S.

Maybe the missing /l/ in salve has something to do with the large percentage of Scots who settled in America in the 18th century.

Walker's Pronouncing Dictionary is available online through Google Books and the Internet archive, both in American and British versions. Here is an edition printed in London in 1792, which pronounces both salve and solder with the /l/.

And here is what I believe to be an American edition from 1800, which pronounces both salve and solder without the /l/. (Look under "soder" to find the entry for solder.)

You have to be careful when looking for the American editions—some of the editions printed in America have the British pronunciations.

Walker's seems to be the first pronouncing dictionary for English, although you might be able to find earlier pronunciations by looking in bilingual dictionaries. However, you can guess what the pronunciation of English words during Middle English was by looking at the spellings. For solder, the OED gives:

Forms: α. Middle English soudur, Middle English soudure, soudour, sowdur, sowdowre; Middle English soudre, Middle English–1500s souder, Middle English–1600s (1800s dialect) sowder (Middle English sowdere, 1500s soweder); 1800s dialect sowther. β. Middle English sawdur, sawdyr, 1500s sawyer; Middle English sawd(e)re, 1500s sawder (1600s sawter), 1500s–1600s saudre, 1600s sauder. γ. 1500s–1700s soder (1600s soader, sodar), 1600s– sodder; 1500s sother, 1600s soather. δ. Middle English souldour, 1500s–1600s soulder (1500s sowl-). ε. 1600s soldure, 1600s– solder,

showing that it was pronounced without the /l/.

For salve, the OED gives:

Middle English sealfe, Middle English (Orm.) sallfe, Middle English sealve, ( salft), Middle English selve, Middle English salf, save, Scottish sawve, Middle English–1800s Scottish saw, Middle English salffe, 1500s saulve, Scottish saufe, 1600s sawf, Middle English– salve,

showing that it generally seems to have been pronounced with the /l/ except in Scotland. However, the OED shows the spelling of half and calf also generally included the /l/ in Middle English.

Answer 2

As requested, here is the OED entry from my 2nd Ed on CD-ROM

c1485 E.E. Misc. (Warton Cl.) 82 To make sowder of tynne.
1513 Douglas Æneid viii. vii. 140 Thai mydlit and thai mixt this feirful souder.
1547 in J. R. Boyle Hedon (1875) App. 137 To the plomer for xxx. lb. of soweder.
1603 Vestry Bks. (Surtees) 52 For five pounde and a half of sowder to mende the leads.
1829 Brockett N.C. Gloss. (ed. 2), Sowther, solder. _.1466 Mann. & Househ. Exp (Roxb.) 323 Item, for ij. li. saw[d]ere, xij. d. 1492 ­3 Rec. St. Mary at Hill (1905) 187 For a ll. di. of sawdyr to sowdyr Þe same pype, xij d.
1539 ­40 in Devon N. & Q. Oct. (1903) 238 Payed for xv. li. of sawdyer for the worke, v.s.
1566 in Peacock Eng. Ch. Furniture (1866) 141 An old crwet whearof was made sawder for the glass windowes.
1602 Shuttleworths’ Acc. (Chetham) 143 To the plumber, for xx pound of pewter to be sawter,..xs.
1667 Primatt City & C. Builder 70 Sawder is about eight pence or nine pence a pound.
_.1575 Gascoigne Wks. (1587) 308 When cutlers..hide no crackes with soder nor deceit.
1576 Act 18 Eliz. c. 15, No Goldsmith..shall..use noe Sother..more then ys necessarie.
1612 Sturtevant Metallica (1854) 36 All compounded mettles of the same kind, as, Pewters, Belmettles, Sodars.
1637 in Parish Bks. St. Julians, Shrewsbury I. 27 (MS.), Received for 9 lbs. of Sodder, 3s.
1660 Boyle New Exp. Phys. Mech. xx. 146 We caus’d a skilful Pewterer..to close it up..with Soder.
1726 Leoni Alberti’s Archit. II. 17 b, The cramps..must be fastened into the sheets with hot sodder.
1750 T. R. Blanckley Naval Expos. 155 Sodder, used by the Plumber for soddering of Pipes.
_.1428 Engl. Misc. (Surtees) 1 þat nane of Þat crafte wirke any lede amang other metaill, bot yf yt be in souldour.
1530 Palsgr. 725, I sowder a metall with sowlder, je soulde.
1574 in Feuillerat Revels Q. Eliz. (1908) 242 For Leade and sowlder with woorkmanshipp.
1611 Cotgr., Souldure,..the knot of soulder which fastens the lead of a glasse window.
1685 Boyle Effects of Motion viii. 99 A gaping crack, which he was fain to fill up with soulder.
_.1724 Swift Prometheus Wks. 1751 III. ii. 150 Goldsmiths say, the coarsest stuff Will serve for solder well enough.