The Welsh language has suffered "a lost decade" as a result of policies since devolution, the former chief of the Welsh Language Board has claimed.
Meirion Prys Jones said there had been a period of "playing politics" with the language which could "sink in a lot of warm water".
The Welsh Language Board's role ended after legislation passed in 2011 created a Welsh language commissioner.
Mr Jones said it had taken "a very long time" to get over those changes.
He was speaking to Welsh language news programme Newyddion 9 ahead of the anniversary of the Yes vote in the 1999 Welsh devolution referendum.
Referring to the Labour-Plaid coalition between 2007 and 2011, Mr Jones said: "We went a bit lost in the middle of the last decade with the One Wales government when there was perhaps an over emphasis on legislating.
"Playing politics has been going on. I think Plaid Cymru saw an opportunity to put a strong structure in place and perhaps it wasn't the right one.
"I certainly think there has been a lost decade. Had we built on what we had in the previous decade we could be in a better position."
Plaid Cymru said it had set firm foundations for the language to prosper.
Census figures in 2011 showed a decline in the number of Welsh speakers.
Language commissioner Meri Huws said there had been questionable decisions involving cuts to budgets.
"There are strong arguments around looking at the Welsh language budget.
"We have faced cuts in the last few years and that has been frustrating and it's caused me pain. I have to question the message behind these decisions."
In 2016 the Welsh Government set a new target of having a million Welsh speakers by 2050.
It favours scrapping the role of Welsh language commissioner and replacing it with a Welsh Language Commission.
The minister responsible for the language, Alun Davies, said a complete re-think of policy was needed.
"Carwyn Jones and I were very clear that we needed to change things, change the way we deal with the language within the government and as a nation," he said.
"If we have change, we have to change everything and that is going to take a lot of time.
"Over the next few months I will be publishing clear targets for this government and this minister."