1. The alternation between initial thhand dd( ́), with the latter usually spelt as t-, in independent and dependent irregular verbal forms respectively in Scottish Gaelic is well known, e.g. thig: tig, thèid: tèid, thàinig: tàinig, thug: tug, thubhairt / thuirt: tubhairt / tuirt, to which we may also add fhuair h-: d’ fhuair. This pattern is also found in Manx, e.g. hig: jig, haink: daink, harragh: darragh, hug: dug, hem (1 sg.): jem (1 sg.), hooar: dooar (Broderick 1984–86, i: 88–92, §§126– 131); it does not extend, however, to dooyrt in Manx (Broderick 1984–86, i: 92, §132). O’Rahilly (1931: 117, 118) explained the development of thhin the present-future forms thig and thèid and the past tense forms thubhairt / thuirt (also their, theirinn, etc.) and fhuair as being due to analogy with nonpresent forms thug, thàinig, thiginn, etc. based on the th-: dpattern they came to display in independent and dependent forms respectively. This is a credible and attractive explanation. The purpose of this brief paper is to suggest that some of the h-initial verbal forms found in Scottish Gaelic, and perhaps also in Manx, may have an older and different origin, and that O’Rahilly’s explanation may hold for some, but perhaps not all, of the relevant verbal forms.