History of Scottish Gaelic
All surviving dialects are Highland and/or Hebridean dialects. Dialects of Lowland Gaelic have become defunct since the demise of Galwegian Gaelic, originally spoken in Galloway, which seems to have been the last Lowland dialect and which survived into the Modern Period. By the 18th century Lowland Gaelic had been largely replaced by Lowland Scots across much of Lowland Scotland. According to a reference in "The Carrick Covenanters " by James Crichton, the last place in the Lowlands where Scottish Gaelic was still spoken was the village of Barr in Carrick: only a few miles inland to the east of Girvan, but at one time very isolated. Crichton gives neither date nor details.
History of Icelandic
Again along with English, Icelandic is unusual among Germanic languages to have conserved, if only at a local level, the pronunciation of the word-initial consonantal cluster : Icelandic "hvað", "hvalur" , more commonly . In English "what", "whale", the is only pronounced in certain dialects. The other Germanic languages have consonantized the cluster: German "was", "Wal-fisch" , Dutch "wat", "wal-vis", Swedish "vad", "val[fisk]". Until the early years of the 20th century Swedish maintained the orthography in words such as "hvad, hvalfisk", which is purely historical. In Danish one writes but does not pronounce : "hvad", "hval-fisk" , while in Nynorsk, in some cases, one writes and pronounces ("kva"), exactly as is usual in modern Icelandic (southern dialect and literary). There are also indications that was originally pronounced .