From: Old-Irish-L [mailto:[log in to unmask]] On Behalf Of Romanas Bulatovas
> A -th- was certainly not pronounced in Old Irish the same way as it is now in modern Irish. It was the same sound as th in English words like "thin".
> By the same token, a lenited -d- was pronounced as English 'th' in words like "this". There is ample evidence for this in Old Icelandic transliterations of Irish names.
Lenited -th- and -d- were certainly not pronounced as the corresponding ModIr. sounds, but personally I doubt that they were the same as Engl. th in thick and father. The Engl. sounds are interdental fricatives; I suspect the OIr. sounds were alveolar fricatives, i.e. produced at the same place where the unlenited stops t and d were produced. This explains better their later development into the ModIr. sounds,