Officials at the largest national park in Wales have voted to only refer to the names of more than 200 of its lakes and waterfalls in Welsh to promote cultural heritage.
Eryri National Park - which changed its official name from Snowdonia last year - wants to 'standardise' the names and protect them for future generations.
It means popular beauty spots known in English as Lake Australia and Lake Bala will now only be referred to by their Welsh names, Llyn Bochlwyd and Llyn Tegid. Llyn Barfog - often referred to as Bearded Lake - will also take its Welsh name.
While some of the 200-plus lakes are already referred to in Welsh, others have an English translation. The National park Authority backed the move unanimously in a vote on Wednesday.
It comes amid a growing clamour from language campaigners to rename Welsh sites in their native tongue.
Eryri National Park - which changed its official name from Snowdonia last year - wants 'standardise' the names and protect them for future generations. Pictured: Llyn Bochlwyd (Lake Australia)
English-speaking tourists have slammed the move as a 'waste of money' and accused officials of targeting the wrong priorities. Pictured: Llyn Tegid (Lake Bala)
Snowdonia officially became known as Eryri last year and and Mount Snowdon - which is in the national park - was renamed to Yr Wyddfa. Earlier this year, the Brecon Beacons national park also rebranded itself as Bannau Brycheiniog.
Bannau means peaks in Welsh while Brycheiniog refers to the kingdom of the fifth-century king Brychan.
The move faced huge opposition - with even Prime Minister Rishi Sunak admitting he would use the old name of Brecon Beacons. National park bosses were accused by both UK Government ministers and Welsh Conservatives for attempting to look 'trendy' with the move.
Earlier this week, it also emerged that Caerphilly and Barry could be renamed as language campaigners push for 'Welsh names for Welsh places'.
After the vote to refer to Snowdonia's lakes in Welsh, Naomi Jones, the head of the National Park Authority's cultural heritage, said the park's 'wealth of names' is a 'treasured part of our cultural heritage'.
'By recommending the standard list of Eryri's lake names the authority ensures that these historical names are recorded for future generations and used extensively in day-to-day life,' she added.
But English-speaking tourists have slammed the move as a 'waste of money' and accused officials of targeting the wrong priorities.
One said: 'Don't agree with this at all. We all speak English.'
Another said: 'What percentage of people in Wales speak Welsh?'
Llyn Bochlwyd, which translates literally as 'grey cheek lake' has been called Australia Lake on maps and in guidebooks over recent years due to its outline resembling the country.
Snowdonia officially became known as Eryri last year and and Mount Snowdon - which is in the national park - was renamed to Yr Wyddfa. Pictured: Llyn Barfog (Bearded Lake)
The National park Authority backed the move unanimously in a vote on Wednesday. Pictured: The mountains and lakes of Snowdonia, looking down from Mount Snowdon
Its original name refers to a legend of an old grey stag which escaped from archers and hounds by plunging into the water and swimming with its head above the surface.
Dr Dylan Foster, who is Cardiff University's head of school of Welsh, said: 'Place names are part of everyone's heritage and in a digital age when information is shared online in an instant having standardised forms of names benefits everyone.
'Projects like this also draw attention to the richness of our local dialects and folklore and allow us to share all kinds of stories about the names that are such an important part of the identities of our communities.'
A petition calling for 'Welsh names for Welsh places' has won sympathy from a Labour Government minister to end English spellings of well-known tourist towns.
This week it emerged that campaigners want Caerphilly cheese to become Caerffili Cheese - and TV comedy Gavin and Stacey's beloved seaside home town to switch from Barry to Barri in the latest English purge.
A 1,300 petition presented to the Cardiff-based Senedd by linguist Mihangel ap Rhisiart called for the use of 'only Welsh names for places in Wales'.
He also hit out at the 'cultural oppression' by the English against Welsh speakers.
Labour's Welsh Language Minister Jeremy Miles - a contender to take over from First Minister Mark Drakeford - said there was 'a strong argument' for using just the Welsh in some cases.
Mr ap Rhisiart said it would show 'respect for Wales as its own nation with its own history and culture; and as a mark of acknowledgement concerning some of the cultural oppression that has historically been inflicted on Wales and her language and culture'.
He added: 'English names might initially continue to be used by some out of habit but in all official avenues and in both spoken and written media, the original Welsh names for places in Wales should be used'.
Minister Mr Miles said: 'We should aim for one spelling when there are only a few letters of difference between the Welsh and English versions'.
It would mean that places with distinctive English names like Cardiff, Swansea or Newport would not be automatically changed to Caerdydd, Abertawe or Casnewydd because of the differences.
But Caerphilly would be changed to Caerffili, Merthyr Tydfil to Merthyr Tudful and Treorchy to Treorchi to fit in with Welsh as the only official name.
It would mean road signs and other official documents being altered over time.
The crackdown follows a campaign for Anglesey to only be known by its Welsh name of Ynys Môn - despite a backlash from locals.