I've tried to do this with a couple of local rivers and can confirm that it is extremely heavy going

The number of speakers has declined but it has never been under threat of extinction, hundreds of thousands of people speak it every day, children are brought up speaking it and over 20% of children attend Welsh medium schools.

It didn't almost get wiped out though, it's spoken by over half a million people, is in the 7% most spoken languages worldwide and isn't even considered endangered by UNESCO.

That's not the only type that are coming on the market though, around Blaenau I'm seeing a lot of terrace houses which have clearly been holiday lets come on the market at prices which should be within the reach if first time buyers.

They may not be affordable as first time buys but they may allow people to move up the property ladder who couldn't before thus freeing up cheaper houses. Around Blaenau I'm seeing a lot of former second homes come on the market which should be within the reach of first time buyers.

The premium can be raised to 300% it's just that no local authority has done so up to now, some are on 200% though.

That's not the same at all, they have always been Eryri and Bannau Brycheiniog.

Meanwhile 95% of my interactions in any given month are in Welsh, but wherever you are Welsh is all around you.

Welsh citizens are much more likely to come across and make use of Welsh than any other language that they might be taught.

Welsh spelling is much more consistent and phonetic than English spelling.

'Lleihau' is definitely wrong, 'adfywiad' is more revival. Geiriadur yr Academi has 'aildarddiant', 'ailgychwyniad', 'ailddechreuad', and 'ailgodiad' for recrudescence in that order.

Not from Wales but rather from what is now Cornwall and the south west of England, Cornish and Breton are Southwestern Brittonic while Welsh is Western Brittonic

It isn't, both are descended from Common Brittonic

The dialectical differences are no more pronounced than between the different dialects of English

The Welsh is in all likelihood a borrowing from French

In a similar vein, Gareth Evans has two novels set in the same time period "The Magic Hornpipe" and "The Girl of Gold", translated into English from Welsh.

They occur only as the nasally mutated forms of p/t/c

It's more west/east than north/south