v1.0
Published 01/10/24
ailm f. [ˈal͡am], gen. ailme -[ə], ‘helm, tiller, the part of a rudder held in the hand’ has a number of apparently related forms: alm, 
[ˈɑ͡ɫ̪ɑm].
almstoc, 
(North Sutherland) alam-stoc (sic) [ɑɫɑmst̪ɔk], alm-stoc (sic) [ɔɫɑmst̪ɔk] (Faclan bhon t-Sluagh˄).
falm, 
[ˈfɑ͡ɫ̪ɑm].
failm, 
[ˈfa͡lam].
falman, 
Easter Ross (pers. comm. Professor Seòsamh Watson).
talman, 
(East Sutherland) [t̪ɑɫəmɑ̃ṉ] (Faclan bhon t-Sluagh˄).
tolman 
(East Sutherland) [t̪ɔɫəmɑṉ] (Faclan bhon t-Sluagh˄); cf. Dorian 1978, 161: talman [tʰɔɫəman].
and falmadair.
[ˈfɑ͡ɫ̪ɑməd̪̥aɾʲ].
MacBain (1896) derives failm and falmadair from (Ice.) hjálm f., recte ON hjǫlm, ‘helm, tiller’, as does Henderson (1910, 255).
Cf. MacLennan (1925), who derives falmadair from hjálm, and Stewart (2004, 410), who derives a(i)lm and fa(i)lm from the same.
McDonald (2009) is more circumspect, pointing out that the Gaelic reflex does not seem to reflect an original já (or jǫ for that matter). De Bhaldraithe (1999, 78) derives (f)ailm and falmadair ultimately from Lat. palma ‘the blade of an oar’. There are several apparently related Irish forms also (see below). The following is an explanation of the origin of the various forms involved, although lack of evidence means it remains conjectural.
Faclan bhon t-Sluagh˄ records failm in Tiree and ailm in Islay, Coll, Skye, Raasay, South Uist 
Cf. McDonald 1972.
and West Sutherland 
Cf. Wentworth 2003.
; al(a)m-stoc is recorded in North Sutherland; talman, tolman in East Sutherland; and falmadair in Scalpay, Harris and Lewis. Further, falmaire, palmaire and palmadair occur in some dictionaries, e.g. Dwelly 1911.
It is suggested here that the primary source for some if not all of these forms is MDut. helmstoc, hence North Sutherland al(a)m-stoc via Scots helmstok, helmestock (recorded in the early 16th century; DOST˄), and MDut. *helm or the semantic derivative or cognate Scots or Eng. helm, 
Perhaps with a pronunciation such as *[hɛlm] or *[hælm].
hence alm and ailm in the Hebrides through loss of initial h- and subsequently falm and failm through prothesis and falmadair through the addition of the suffix ‑adair (EG ‑(a)tóir); so also falman in Easter Ross with the suffix ‑an (EG ‑án), but talman and tolman in East Sutherland via *halm and delenition and back-formation of /h/ > /t/. If falmaire actually occurred in Scottish Gaelic, it can be explained through the use of an alternative suffix, viz ‑aire (EG ‑(a)ire); palmaire and palmadair might be the result of delenition and back-formation of /f/ > /p/, although palmaire may simply be a dictionary borrowing from Irish.
The form ailm does not occur in Irish, and de Bhaldraithe points out that the failm of Irish dictionaries is likely to be a borrowing from Scottish Gaelic dictionaries. On the other hand, heilm, heileam is found in Munster and heilim, hailim in Ulster, although de Bhaldraithe sees these as examples of the use of the English word helm: ‘[i]s é is dóiche gurbh é an focal Beurla helm a bhí á rá ag Gaeilgeoirí na hÉireann’ (p. 78).
Ir. falmadóir occurs, along with several variants: falmadóir and halmadóir chiefly in Connacht; talmadóir in Co. Clare; talmadóir and halmadóir in Co. Mayo; almadóir and halmadóir in Galway; and falmatar in Rathlin.
De Bhaldraithe also derives Ir. falmaire from Lat. palma, via Ir. palmaire, with p yielding f as found in the doublet palmaire ~ falmaire ‘pilgrim’, from Lat. palmarius.
For further examples of p < f in Irish, see Ó Curnáin 2007 I, 253; in Scottish Gaelic, see Calder 1972, 65–66.
However, the fact that palmaire does not apparently occur in speech or literature suggests the development may in fact have been the other way round: falmaire > palmaire, with falmaire ‘helm’ deriving ultimately from the same source as falmadóir, falmadair etc.
The development of the MDut. helmstoc and *helm or Scots or Eng. helm to Irish and Scottish Gaelic in this way seems semantically and phonetically plausible and could have been initiated in the context of Dutch fishing enterprise; 
For Dutch fishing in northern and western Scotland in the early 17th century, see MacCoinnich 2015, Chap. 5.
the variety of forms and their range in Irish and Scottish Gaelic is due to dialectal variation and no doubt interdialectal borrowing.