The first minister has been criticised after English-only leaflets were sent in his name to some constituents ahead of May's Welsh Parliament election.
They were delivered to residents in an area of Mark Drakeford's Cardiff West consistency, carrying a photograph of him with the heading "Labour news".
Welsh Labour said they were sent out by the local party group and leaflets by Mr Drakeford will be bilingual.
Rivals have accused the Welsh Labour leader as being "hypocritical".
The Welsh government announced plans in 2016 to almost double the number of Welsh speakers from the 562,000 recorded in the 2011 census.
"Leaflets coming from the first minister should be bilingual - in Welsh and English," said Cardiff West Plaid Cymru candidate Rhys ab Owen.
"It is one thing to set a target of a million Welsh speakers by 2050, but another to act on that. The fact that he's sending English-only leaflets show he isn't practising what he is preaching.
'Contempt towards the language'
"To normalise the language it is important things are bilingual and receiving bilingual leaflets from the first minister is imperative."
He accused Mr Drakeford of being "hypocritical".
Neil McEvoy, of the Propel Party, said: "They have shown contempt towards the language... I am disappointed but am not surprised.
"At the end of the day, it doesn't matter because the language is growing. It has changed a lot here in Fairwater. I can hear the language being spoken in the shops and on the streets."
The Abolish the Welsh Assembly Party said in a statement: "It is the hypocrisy that stinks. As first minister, Mark Drakeford spends untold millions cutting down forests to translate all his government leaflets into Welsh.
"Yet, when he is spending his own Labour Party money, he admits it is a ridiculous waste, and sensibly just prints his message in English."
Mr Drakeford, who has been Wales' first minister since 2018, has held his Cardiff West seat since 2011 and 2021 Senedd election leaflets supporting him were sent to homes in the Fairwater area of the city.
Welsh Labour said it was "aware a monolingual version of a leaflet by the local Labour party had gone out in some areas of Cardiff West" but Mr Drakeford's "election leaflets including the freeposts, are and will continue to be, bilingual".
The Welsh Liberal Democrats, Welsh Conservatives and the Green Party have also announced candidates standing in the Cardiff West Constituency - Heath Marshall, Sean Driscoll and David Griffin respectively - but did not offer any comment.